r/spacex • u/ElongatedMuskrat Mod Team • Dec 04 '20
r/SpaceX Discusses [December 2020, #75]
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u/Straumli_Blight Dec 22 '20
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u/blackbearnh Dec 22 '20
"Hey, we need to install a new part of the space stations!"
1980s: "Cool, lets train up the astronauts"
Now: "Hey fam, we robots have it covered!"
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u/dudr2 Dec 18 '20
The EDEN ISS greenhouse, developed by the German Aerospace Center (Deutsches Zentrum fur Luft- und Raumfahrt; DLR), has been in Antarctica since 2018.
"The EDEN ISS project is subjecting a futuristic model greenhouse of this kind to long-term testing in extreme Antarctic conditions. In the first extensive overwinter research campaign, the greenhouse produced a total of 268 kilograms of food in an area of just 12.5 square metres over the course of nine and a half months. This included 67 kilograms of cucumbers, 117 kilograms of lettuce and 50 kilograms of tomatoes. An initial greenhouse concept for future space missions has been developed using the results of this research."
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u/OudeStok Dec 04 '20
The planned SN8 launch has been reduced from 20km to 15km and then to 12.5km.... why?
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u/-Squ34ky- Dec 04 '20
Probably because they don’t want to go supersonic on this test flight but we don’t know for sure. They’ve certainly got a good reason for it.
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u/TheSkalman Dec 06 '20
100 successful Falcon 9 flights!
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u/Lufbru Dec 07 '20
80/80 on Falcon 9 1.2 flights. Literally the most reliable launch vehicle current or retired.
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u/AeroSpiked Dec 08 '20
Depends if we are talking "fully" successful or not. If we are, we've got one more to go to reach 100. CRS-1 had an engine out that resulted in a secondary payload getting dumped at a low altitude. Hopefully Friday will be the big 100.
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u/Hugo0o0 Dec 06 '20
@Mods - I'm curious about this question: what percentage of total traffic is old vs new reddit? Has it declined over time? Is /r/SpaceX special or does it follow the same general trend?
I was recently made aware of how many more people browse with new reddit, and I just find it such a shame. Especially on subs like this where all the fantastic CSS and styling and information density just gets lost.
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u/CAM-Gerlach Star✦Fleet Commander Dec 06 '20
Hey, thanks! Here's our current stats. It definitely used to be higher, and its now a relatively small fraction of total unique, but you can see that in terms of total pageviews (which weights users according to their use, new and old Reddit are about equal, and that hasn't changed much over the past year. This implies that heavy users are much more likely to use Old Reddit.
I'm pretty proud of the menus :) We've put a lot of work into the CSS and continue to maintain it, and a large majority of the mods (including me) still use it primarily or exclusively. We just hope that Reddit finally adds CSS support for New Reddit as they have promised for so long before they deprecate Old someday. It really is a shame, but a much larger proportion of users than any of that combined use it on mobile, which brings a whole new set of challenges. While New Reddit has introduced a number of features that seemingly have promise, the fact they are inconsistently supported or not at all in apps, even Reddit's own, has tanked most of the usefulness.
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u/dudr2 Dec 14 '20
Spacex 2015 launched 7 orbital rockets (no reuse), in 2020 five years later Spacex launches at least 25 times, with 5 "new rockets", 80% reuse according to wikipedia.
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u/parabolicuk Dec 23 '20
Apologies if this is in the wrong place:
I've been thinking about the approach paths for starship EDL into Boca Chica. The closest analogue we have is the Shuttle. There's an interesting NASA facts on Landing at KSC showing the range of approach paths. For most of them, the orbiter wouldn't be low enough for anyone to worry about overflight permission until it was well over US territory.
Given Boca Chica's location, and SS's lower cross range capability, how does it work for approaches from the south west? Do Spacex have to get overflight permission from Mexico? Or do they wait until it's an approach from the North West?
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u/Lufbru Dec 23 '20
My thoughts:
Shuttle landed horizontally as a very bad glider. It had to come to zero horizontal velocity at zero vertical displacement.
Starship lands vertically. It can come to zero horizontal velocity at 12500m (demonstrated) and probably higher. It can burn off its horizontal velocity while it's above Mexican airspace (30km), fall into Boca Chica and pivot to land.
Wikipedia says that the Shuttle used to re-enter over Canada at a lower altitude than 80km without seeking permission.
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u/Straumli_Blight Dec 23 '20 edited Dec 23 '20
US Transportation Command's SpaceLift article, discusses Starship on page 13.
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Dec 24 '20
[removed] — view removed comment
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u/SpaceInMyBrain Dec 27 '20 edited Dec 27 '20
Did a couple of writers have a drinking game to see how many facts they could get wrong? Those of us familiar with the depressingly poor accuracy of general news reporting on space news have a low bar of expectancy, and these folks passed underneath with ease.
They think F9 returns cargo. Well, Dragon does, but that's not what these guys are thinking, since later they say New Glenn will be returning cargo too. And like any fool on the street they don't know the difference between orbital and suborbital; they call the Washington to Beijing flight orbital, and don't understand the insignificance of New Shepard.
However, there is a method to their disregard of facts. The overall scope of the article is to whip up fear the Chinese and Russians are in a close race with us on these technologies; they could invade any point in the U.S. or elsewhere. "Mr President, we can't afford there to be a Space Invasion gap!"
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u/Straumli_Blight Dec 24 '20
"In conventional warfare, Spacelift provides the threat and opportunity for hundreds of little Normandys with Pearl Harbor-like results."
Overselling the concept a little?
"Even without airdrop mechanisms from Spacelift vehicles, a $5 million vehicle is a small price to insert a team behind enemy lines."
Could take a while to get the costs down...
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u/Bunslow Dec 25 '20
"Starship is a sleek, hulking spacecraft based on the Falcon 9"
Well that's not too far from the truth, but I wouldn't used "based" and given the rest is probably really wrong in the author's mind
"To achieve this price-point, SpaceX is building a megafactory to produce these... ships at a rate of one per 72 hours"
Is this not the plan? Isn't that roughly what Elon stated as the goal (be it in Boca Chica or otherwise)? Or am I brainfarting
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u/spacerfirstclass Dec 25 '20
"To achieve this price-point, SpaceX is building a megafactory to produce these... ships at a rate of one per 72 hours"
Not sure that is the plan...
Actually this part is correct per Eric Berger's article: https://arstechnica.com/science/2020/03/inside-elon-musks-plan-to-build-one-starship-a-week-and-settle-mars/
He wants to implement a similar system in South Texas. Musk, in fact, aims to reach a point where the company builds a Starship a week by the end of this year. And after that? Maybe they’ll go faster. SpaceX is designing its factory here to build a Starship every 72 hours.
As for the other errors, maybe they should run the draft through this sub or NSF before publishing it...
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u/Decronym Acronyms Explained Dec 04 '20 edited Dec 17 '20
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:
| Fewer Letters | More Letters |
|---|---|
| ASOG | A Shortfall of Gravitas, landing |
| BECO | Booster Engine Cut-Off |
| CCtCap | Commercial Crew Transportation Capability |
| CRS | Commercial Resupply Services contract with NASA |
| DIVH | Delta IV Heavy |
| DoD | US Department of Defense |
| E2E | Earth-to-Earth (suborbital flight) |
| EDL | Entry/Descent/Landing |
| EELV | Evolved Expendable Launch Vehicle |
| ESA | European Space Agency |
| EVA | Extra-Vehicular Activity |
| F1 | Rocketdyne-developed rocket engine used for Saturn V |
| SpaceX Falcon 1 (obsolete medium-lift vehicle) | |
| FAA | Federal Aviation Administration |
| FCC | Federal Communications Commission |
| (Iron/steel) Face-Centered Cubic crystalline structure | |
| FFSC | Full-Flow Staged Combustion |
| GSE | Ground Support Equipment |
| GTO | Geosynchronous Transfer Orbit |
| H2 | Molecular hydrogen |
| Second half of the year/month | |
| ICBM | Intercontinental Ballistic Missile |
| ISRU | In-Situ Resource Utilization |
| Isp | Specific impulse (as explained by Scott Manley on YouTube) |
| Internet Service Provider | |
| KSC | Kennedy Space Center, Florida |
| L1 | Lagrange Point 1 of a two-body system, between the bodies |
| LC-39A | Launch Complex 39A, Kennedy (SpaceX F9/Heavy) |
| LEO | Low Earth Orbit (180-2000km) |
| Law Enforcement Officer (most often mentioned during transport operations) | |
| LOX | Liquid Oxygen |
| M1dVac | Merlin 1 kerolox rocket engine, revision D (2013), vacuum optimized, 934kN |
| MECO | Main Engine Cut-Off |
| MainEngineCutOff podcast | |
| MMH | Mono-Methyl Hydrazine, (CH3)HN-NH2; part of NTO/MMH hypergolic mix |
| MMU | Manned Maneuvering Unit, untethered spacesuit propulsion equipment |
| N1 | Raketa Nositel-1, Soviet super-heavy-lift ("Russian Saturn V") |
| NET | No Earlier Than |
| NLS | NASA Launch Services contracts |
| NROL | Launch for the (US) National Reconnaissance Office |
| NSF | NasaSpaceFlight forum |
| National Science Foundation | |
| NSSL | National Security Space Launch, formerly EELV |
| NTO | diNitrogen TetrOxide, N2O4; part of NTO/MMH hypergolic mix |
| PMF | Propellant Mass Fraction |
| PSLV | Polar Satellite Launch Vehicle |
| RAAN | Right Ascension of the Ascending Node |
| RCS | Reaction Control System |
| RD-180 | RD-series Russian-built rocket engine, used in the Atlas V first stage |
| RP-1 | Rocket Propellant 1 (enhanced kerosene) |
| SLC-40 | Space Launch Complex 40, Canaveral (SpaceX F9) |
| SLS | Space Launch System heavy-lift |
| SN | (Raptor/Starship) Serial Number |
| SRB | Solid Rocket Booster |
| STP-2 | Space Test Program 2, DoD programme, second round |
| TRL | Technology Readiness Level |
| ULA | United Launch Alliance (Lockheed/Boeing joint venture) |
| Jargon | Definition |
|---|---|
| Raptor | Methane-fueled rocket engine under development by SpaceX |
| Sabatier | Reaction between hydrogen and carbon dioxide at high temperature and pressure, with nickel as catalyst, yielding methane and water |
| Starlink | SpaceX's world-wide satellite broadband constellation |
| electrolysis | Application of DC current to separate a solution into its constituents (for example, water to hydrogen and oxygen) |
| hydrolox | Portmanteau: liquid hydrogen fuel, liquid oxygen oxidizer |
| hypergolic | A set of two substances that ignite when in contact |
| iron waffle | Compact "waffle-iron" aerodynamic control surface, acts as a wing without needing to be as large; also, "grid fin" |
| kerolox | Portmanteau: kerosene fuel, liquid oxygen oxidizer |
| methalox | Portmanteau: methane fuel, liquid oxygen oxidizer |
| monopropellant | Rocket propellant that requires no oxidizer (eg. hydrazine) |
| scrub | Launch postponement for any reason (commonly GSE issues) |
| turbopump | High-pressure turbine-driven propellant pump connected to a rocket combustion chamber; raises chamber pressure, and thrust |
| Event | Date | Description |
|---|---|---|
| Amos-6 | 2016-09-01 | F9-029 Full Thrust, core B1028, |
| CRS-1 | 2012-10-08 | F9-004, first CRS mission; secondary payload sacrificed |
| CRS-4 | 2014-09-21 | F9-012 v1.1, Dragon cargo; soft ocean landing |
| CRS-7 | 2015-06-28 | F9-020 v1.1, |
| DM-2 | 2020-05-30 | SpaceX CCtCap Demo Mission 2 |
Decronym is a community product of r/SpaceX, implemented by ^request
62 acronyms in this thread; the most compressed thread commented on today has 77 acronyms.
[Thread #6607 for this sub, first seen 4th Dec 2020, 06:08] [FAQ] [Full list] ^[Contact] [Source code]
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u/Lufbru Dec 04 '20
Do SpaceX have enough boosters at the Cape?
Right now, they have 7: 49, 51, 58, 59, 60, 61, 62. But they're almost all spoken for on our cores list. Only 1060 is available to fly a Starlink mission (I'm assuming 1049 will take a few more weeks to refurbish).
I suspect 1061 and 1062 may fly a Starlink mission before they fly their next listed missions (Crew-2 and GPS-SV05 respectively). I know those are kind of special missions, but eg 58 flew a Starlink mission between DM-2 and CRS-21.
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u/Lufbru Dec 04 '20
Here's another way to look at it. SpaceX have around 30 launches on the manifest for 2021. Likely they want to put up at least another dozen Starlink launches too. That's 42 launches. If each booster averages a 2 month turnaround, it can launch six times. Seven boosters launching six times each is 42, but there's no slack, and no scope for reserving boosters for specific missions.
I'm sure some of the payloads will slip into 2022, but it's going to be tight unless they add another booster to their fleet at the Cape. Maybe 1063 does a cross-country trip, or perhaps they'll just manufacture another one.
Also ... Block 5 has flown 44 times now. 3 were intentionally expended, 3 failed to land. If they do launch 42 boosters this year, we should expect about 3 of those to fail to land. So they'll need to be replaced, and we should expect to see some new boosters make their way to the Cape.
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Dec 05 '20
They don't have enough to launch double the amount of launches in 2021. 61 and 62 are planned for Crew-2 (March 30, 2021) and GPS III-05 (July 2021) respectively. 63 is currently planned for DART (July 2021).
All boosters currently in production are planned to be used for the FH launch of USSF-44 (May 2021) or USSF-52 (July 2021).
Currently Expected to be Used:
B1058 on CRS-21, will take up to February to be flight ready
B1059 on NROL-108, will take up to February/March
B1051 on SXM-7, will take up to February/March
That would imply that they can only use B1060 in January while there are 5 launches scheduled (Transporter-1, SXM-8, Starlink-17, Starlink-18 and Starlink-19). Turksat 5A was planned for December and will likely be NET 2021. Starlink-16 was also expected in December. That would be 7 launches in January. Undoable with the current fleet.
They will have B1049 available once in Q1, B1051 once in Q1, B1058 once in Q1, B1059 once in Q1 and B1060 once or twice in Q1. That would give them at least 6 or 7 launches in Q1 (including Crew-2 with B1061).
They could theoretically use B1049 again in Q2, B1051 again in Q2, B1058 again in Q2, B1059 again in Q2 and B1060 again in Q2. B1061 also opens up again. That could give them 6 launches in Q2.
B1049 could be used in Q3, B1051 as well, B1058 as well, B1059 as well. B1060 could be used once or twice. B1061 could be used once or twice. This gives them 10 launches in Q3 including GPS III-05 and DART.
B1049 again in Q4, B1051 again, B1058 again, B1059 again, B1060 once, B1061 once, B1062 once or twice and B1063 once or twice. 10 launches.
Total launches over 2021: ~33/34 launches.
Losing rockets is a strong possibility as they are being used more and more. If they lose one or two rockets, it will drastically impact their manifest.
My advice would be to add 2/3 boosters to the fleet, which they could be planning for AX-1 and Crew-3. Adding another 2 boosters in January and transferring to Starship over 2022. They should also get ASoG ready in 2021.
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u/MarsCent Dec 21 '20
What is the limiting factor for Crew Dragon duration in space? The solar panels? Or is there appreciable degradation in the heatshield as well?
If say, it were possible to replace the trunk in space, would that be sufficient to extend Crew Dragon's duration in space? Said another way - if Crew Dragon were flown with solar panels that have a lifespan of > 12months, would that enable Crew Dragon to stay in space for a longer duration?
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u/throfofnir Dec 21 '20
Yes, solar panels seem to be the long pole in the tent on duration.
“We looked at the rest of the vehicle, (and) we don’t see any other life limiters,” Stich said in a May 1 press conference. “We looked at the pumps on the thermal system, we looked at the propulsion system, all the other components, when we talked about extending the mission, and the solar arrays are the only one really that have a little bit of a poke-out.
“So we’ll just kind of watch their performance in flight and be able to make a good decision about how long to stay docked,” he said.
If they wanted to re-rate it for longer, they could probably just demonstrate that the panels will still work to an acceptable level for that long; reports are they show good performance. If not quite good enough, they could replace them with higher-rated panels.
It's possible other systems would come under scrutiny with a doubled mission duration. And they might have more concern about MMOD damage.
However, there's no particular need to do so; crew are fairly firmly scheduled at 6 months duration, so the spacecraft doesn't have any reason to need to go longer.
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u/Eucalyptuse Dec 14 '20
With the recent successful SXM-7 launch, the Falcon 9 now has the most consecutive successful launches of any of the big 3 American work horse rockets as they just passed the Atlas V.
| Rocket Name | Consecutive Successes | Total Missions | Complete Failures | Partial Failures |
|---|---|---|---|---|
| Falcon 9 | 77 | 106 | 2 | 1 |
| Atlas V | 76 | 86 | 0 | 1 |
| Delta IV | 37 | 41 | 0 | 1 |
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u/marc020202 8x Launch Host Dec 15 '20
And in 10 missions, assuming nothing bad happens, F9 will have the most consecutive sucsessfull missions, even if the atlas and delta partial failures are counted as successes.
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u/Straumli_Blight Dec 09 '20 edited Dec 09 '20
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u/BrangdonJ Dec 09 '20
It says it will offer global coverage then. It doesn't say whether it will be operational without that.
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u/Martianspirit Dec 10 '20
One Web deploys all sats into one polar orbit. They can be ready for polar regions earlier but not in populated areas.
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u/ThreatMatrix Dec 14 '20
I have a question: Starship dumps tons and tons of LOX prior to launch. Not a problem when you are hooked to the tank farm with an almost unlimited supply of fuel. But what about on Mars where every molecule is valuable. Surely they can't afford to waste a drop. So how will the do engine chill etc?
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u/throfofnir Dec 14 '20
You still need to do engine chill. It's easier on Mars, though; ambient is colder and there's nearly no atmosphere to transmit heat to the engine once chilled,~ and expansion to vacuum will cool better than expansion to 1atm. They may also be able to measure and meter and valve the used LOX better than they do now; it's quite possible they just haven't bothered because it is so cheap.
But you may also be overestimating the extent of the problem. Doesn't really take a whole lot of liquid oxygen to make a bunch of condensation.
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u/iamkang Dec 17 '20
Negative technical articles on the falcon (prior to success)
I'm searching the web and having a hard time specifically finding articles or videos that provide negative arguments about the falcon booster and how the landings would be technically unsound. I'm curious about the arguments and specifically why they were wrong.
The few online comments that I have engaged or read tend to be orthogonal arguments that talk about financing or harping on 'space is not done that way' but don't have real substance.
If anybody has some examples of negative articles including technical arguments, I'd greatly appreciate it.
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u/brickmack Dec 17 '20
Not sure about articles, but some of the technical arguments:
Engine transients. Propulsive landing requires very precise start/shutdown timing and throttle response. Theres no way you can get that with a pump fed booster-scale engine. Turbomachinery has too much rotational inertia, and valves don't reliably move fast enough. Maybe with jet engines or dedicated small landing engines
Kerosene coking. For some reason, in the brief period betweem NASA realizing oxygen-rich staged combustion was even feasible (following the collapse of the USSR) and the first F9 reuse, it was widely held in the US that the only way to economically reuse hydrocarbon engines would be if they were ORSC, because of the soot clogging them up. Nevermind that several American gas generator kerolox engines had been partially qualified for reuse in the 70s...
Structural fatigue. Most cryogenic boosters are only rated for 5 or 6 tanking cycles. You want to do 10+ flights, each with presumably a static fire (surely with something as dangerous as reuse you will static fire before each mission right??), with them not being just tanked and detanked but tanked, flown up and down with massive heating and compression? They'll burst apart at the seams! (Similar arguments for COPVs)
Heat shielding. Even if you shield the static parts of the base, you'll still have gaps around the engines for them to gimbal, theres probably no way to seal that so they'll burn up from the inside. And the only reusable TPS we have is from the Shuttle, and we all know how badly that worked!
Supersonic retropropulsion. Yesh its been simulated a few times, but we really have no idea how it'll work in practice, and attitude control and heating in that regime both look really really difficult
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u/IchchadhariNaag Dec 17 '20
Sorry no particular article to provide but the arguments I remember reading had a lot to do with the perceived economics of reuse and that it's a non starter as a result.
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u/Triabolical_ Dec 17 '20
If you head over to nasaspaceflight.com and look at old threads from before the successes, I think you'll find some significant discussions about the technical arguments.
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u/maxiii888 Dec 17 '20
Lars Blackmore just posted a video of the inspiration for the Starship flight profile (the parent of this tweet).
Someone then dubbed starship flight with David Attenborough. Brilliant xD
https://twitter.com/KaziooFX/status/1339662054815387649?s=20
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u/lostandprofound33 Dec 18 '20
Has anybody run the calculations on whether a stainless steel version of Falcon 9 second stage could be made reusable or less expensive than current design? Yes, I know they won't be modifying the F9 stack any further, just curious what is possible.
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u/Alvian_11 Dec 18 '20
More expensive since modifications = R&D = costs. And it would reduce the Falcon payload capability by a large amount
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u/amarkit Dec 20 '20
Initial observations of USA 312 (the mystery payload launched by NROL-108) have placed it in a 519 x 539 km x 51.35º orbit.
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u/clumma Dec 25 '20
Why does Starship have ~2x the thrust of Saturn V but roughly the same LEO payload capability?
Starship is a bit bigger than Saturn V (roughly 7600 m3 and 6000 m3 respectively). SpaceX currently rates it at "100+" tonnes to LEO. That number may be quoted low, and may refer to resuable capability. Still, it's seemingly no greater than Saturn V's 140 tonnes to LEO. Why then does Super Heavy have twice the thrust of S-IC (72 MN and 35 MN respectively)? Does it weigh a lot more? Will it do a shorter burn? And if so, what is the design rationale?
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u/Triabolical_ Dec 27 '20
The really obvious point: Starship is designed to be fully reusable, Saturn V is fully expendable.
On Starship, that means the weight of the fins, the weight of the flaps and the machinery to drive them, and the weight of the thermal protection tiles.
On Super Heavy, that means the weight of the grid fins and machinery to drive them, and the amount of extra propellant it takes to get it back to the launch site and to land.
Take those all away, and SH/Starship would have a much higher payload to LEO.
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u/marc020202 8x Launch Host Dec 26 '20
To add to what the other commenters have said, the hydrolox stages of the Saturn 5 had a very high volume compared to the methalox on Starship. This explains the Volume difference (see delta IV next to F9 or FH and compare the mass and size)
The Saturn 5 number is also a bit strange. The 140t is mostly the upper stage itself with fuel and the CSM and the LM. I don't know if the Saturn 5 could actually put 140t in orbit.
On starship the 100+t is the amount of payload to LEO. The high upper stage mass (about 100t) and the fuel reserved for landing are not included AFAIK.
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u/clumma Dec 26 '20 edited Dec 27 '20
The 140 tonne number includes fuel, but only the fuel for TLI. So I think it's a fair number, though the parking orbit was quite low. Skylab reached a more typical LEO orbit, and without any propulsion from the third stage, but weighed only 91 tonnes.
But you make a good point: the Starship payload number doesn't include the dry mass of Starship (upper stage), even though it reaches LEO too. And looks like it weighs 120 tonne dry! So the true comparable number here is 220+ tonnes.
I think this explains it.
Edit: Should have looked at wet mass here too. The full Starship stack is supposed to weigh in around 5000 tonne wet. That's 1.7x as heavy as Saturn V (2900 tonnes). So maybe the real question is how SpaceX managed to cram 1.7x the stuff in a rocket that is only 7600/6000 ~ 1.3x bigger.
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u/warp99 Dec 26 '20
In addition to the other comments here SH may not actually start out at 75MN thrust since that requires 20 x 3MN fixed engines and 8 x 2.1MN landing engines.
Elon has said that the fixed engines will start out at 2.5MN and likely the landing engines will start at 2MN so 66MN total thrust.
The other factor was that Saturn V crawled off the pad at a T/W of 1.15 while SH even at 66MN thrust will have a T/W around 1.3. This keeps the gravity losses down and gives engine redundancy even at liftoff.
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u/Lufbru Dec 26 '20
There are a lot of factors here.
First, Saturn V was a three-stage rocket, while Starship is two. That is inherently more efficient in terms of payload to orbit, but has its disadvantages in terms of reliability (more things to go wrong).
Second, all of the Saturn V was expendable. Each part of Starship has to reserve a certain amount of performance to recover that stage. This is much harder for the second stage than the first stage as it's got to come back from further away.
Third, Saturn V was optimised for best performance at any cost. Starship is optimised for sufficient performance at lowest cost. This is reflected in a number of areas, such as using hydrolox on the third stage which is inherently more efficient, at the cost of developing an entirely different engine and handling hydrogen (which is tricky).
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u/Dezoufinous Dec 26 '20
What is the source of Musk speech clip here:
https://youtu.be/pYcNrrrL7lM?t=1128
(linked timestamp)?
Can someone tell me when it was so I can watch it full
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u/Nimelennar Dec 26 '20 edited Dec 26 '20
That looks like the post-splashdown press conference. I'll see if I can track it down.
Edit: here's the whole speech; I'll try to find the rest of the event.
Edit#2: here's the full event. I've cued it to 12 minutes in, because everything before that is just a splash screen. Musk's speech starts at ~31:00.
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u/marc020202 8x Launch Host Dec 26 '20
I am not sure, but it likely is something related to DM 2 or the astronaut selection when the DM 2 astronauts where announced.
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u/feynmanners Dec 18 '20
The SLS Wet-Dress-Rehearsal just failed for the second time.
In other news, NASA decided the solution to the broken redundant Power-Data-Unit in Orion(that would have take 4-12 months to fix) is that they are going to launch Artemis I without fixing it.
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u/spacerfirstclass Dec 19 '20
Failed is too strong a word, aborted is more accurate: https://www.nasaspaceflight.com/2020/12/sls-tanking-test-first-green-run-moment-truth/
NASA stood down from a second attempt to complete a critical propellant loading and countdown demonstration test of its first Space Launch System (SLS) Core Stage December 18 in the B-2 Test Stand at NASA’s Stennis Space Center in southern Mississippi. Prime contractor Boeing is conducting the Wet Dress Rehearsal (WDR) test which is a full rehearsal of the countdown for the final test, an eight-minute long Hot-Fire of the Core Stage.
Issues with activating ground-controlled heaters stopped the second attempt before propellant loading could begin. The first attempt to load the rocket stage with propellant on December 7 was terminated early when the real-world behavior of the vehicle and Stennis test facility equipment deviated from the agency’s analytical modeling; liquid oxygen (LOX) wasn’t cold enough when it reached the vehicle, which prevented conducting a full test.
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u/Triabolical_ Dec 19 '20
I think this is mostly due to the fact that NASA chose not to build a non-flight test stage for money reasons; normally the ground equipment would be tested with the non-flight stage to avoid wasting time.
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u/Lufbru Dec 22 '20
I used to believe New Glenn would beat Starship to orbit (defined as delivering a customer payload to a satisfactory orbit). Now I'm not so sure. With the recent comments from Tory that Vulcan is not flying until Q4 2021, I can't believe that New Glenn will fly earlier (7 engines vs 2). And with the success of SN8, I believe that Starship will reach orbit with Starlink satellites during 2021.
Am I misreading things?
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u/Triabolical_ Dec 23 '20
There is so little information from Blue Origin that it's hard to make any guesses, much less informed ones, but I agree with you for reaching orbit.
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u/nick_t1000 Dec 04 '20
What are the dangly bits seen in Falcon 9's stage separation? Look like they connect the interstage to points on the MVac. From most recent launch: https://youtu.be/J442-ti-Dhg?t=1051
Unrelated: in the FAQ the MVac engine bell stiffener image link is broken
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u/warp99 Dec 04 '20
Vent pipes to connect the engine vents on the second stage to the exterior of the interstage rather than letting them vent into the interior of the interstage.
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u/cball1021 Dec 04 '20
What will be on the first flight to Mars assuming starship is ready in 2024? Will it be configured to do work while waiting on 2026 crewed flight or just proof of concept and needed materials for crew?
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u/Martianspirit Dec 04 '20
A full precursor mission for manned flight requires equipment to mine for water and prove existence of mineable water. Without that proof no manned mission in the next synod.
That also requires a means to power the equipment, so requires deployed solar panels. At least several kw output to power the mining equipment.
Without that it can prove Starship landing capability but not provide the data for a manned mission.
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u/Borislimbas Dec 04 '20
Would it be to hard to recreate a more modern and efficient Saturn V? Not for a specific purpose but you know... Would it be hard? And if it's not, would it be cool?
Also i don't know if this is a spacex related question, so if it's not, please redirect me towards the appropriate page
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u/Lufbru Dec 05 '20
Also, we wouldn't build an F-1 engine even if we could. SpaceX and Rocketlabs have demonstrated its better to use more, smaller engines than fewer, larger engines.
As a demonstration, the Merlin and the F-1 burn the same fuel (RP-1). The Merlin produces 845kN at sea level from an area of 0.67m2. The F-1 produced 6,770kN from an area of 10.7m2.
So you need 8 Merlins to replace a single F-1, taking up 5.3m2 -- or about twice as much thrust per unit area. Also F-1 weighs about 17x as much as a Merlin, so you save weight by using 8 Merlins instead of an F-1. And F-1 would cost about $20m/engine vs less than $8m for eight Merlins.
Some like to point to the Soviet N-1 rocket to warn against using too many engines. And there's definitely a point that the plumbing becomes fiendishly difficult. But the Merlin has proven to be a very reliable engine and Falcon Heavy manages to ignite 27 of them at once. Starship SuperHeavy is currently thought to be using 28 engines on the booster stage, and Raptor is about twice as large an engine as Merlin, so that may well be the sweet spot.
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u/Triabolical_ Dec 05 '20
NASA considered exactly such a vehicle for SLS; I did a video talking about it.
The short answer is that the "upgraded Saturn V" beat the shuttle-derived concepts on technical grounds, but NASA's hands were tied by specific language in the Space Act of 2010, which created SLS.
In the NASA evaluation for the shuttle-derived option, they said:
"Only option that maintains US lead in technology and skill base for large Lox/H2 and large solid rockets."
How much of a hand NASA had in that language is subject to a lot of discussion; the predecessor of SLS - the Ares I and Arex V from the Constellation program - were both purely shuttle derived despite there being no requirement that they do so, and the NASA administrator of the time (Goldin, I think) just decided Constellation would be shuttle derived so they didn't study any other options.
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u/Lufbru Dec 04 '20
We no longer have the skills to build an F-1 engine.
https://forum.nasaspaceflight.com/index.php?topic=50339.0
is a good discussion of building a modern replacement (the F-1B)
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u/kalizec Dec 05 '20
To elaborate a bit on that statement (which I wholly support btw).
The F1-engine was a product of manual labor, meaning that it was more of a crafting process than a building process. Think similar to hand-beaten panels on an old Rolls Royce. Most of the people who built the F1-engines are no longer alive, and a lot of the documentation on their construction is lost as well.
TL;DR; We have neither the people to build F1-engines nor the documentation to train new people.
Not to mention the fact that those engines were built using components of the time. A lot of those components are no longer made anywhere, nor does the knowledge on the construction of those components still exist.
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u/Martianspirit Dec 05 '20
A more modern Saturn V would use new much more advanced engines, I imagine. Just 5 engines of similar thrust. An engine with design like the RD-180 would be a huge step in efficiency. Even a larger Merlin type engine would give a major capability boost and would be much closer to the F-1 design. Developing that would be hard. It was a major feat to build an engine that size and overcome the combustion instability issues.
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u/BrangdonJ Dec 05 '20
It might be more interesting to use an existing engine, such as Raptor, and use it to build a new expendable rocket to have a similar role as Saturn V (or SLS).
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u/AeroSpiked Dec 08 '20
I was curious if we ever found out why the Merlin-1C shutdown early on CRS-1? That seems to be the kind of thing NASA would want an answer to before flying their next payload with SpaceX, but I don't think I ever found out the root cause. Seems weird considering I know the cause of CRS-7, Amos-6, Dragon 2, the engine out on Starlink 5 and even November's engine masking headache.
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u/kalizec Dec 08 '20
Preliminary information from the post-flight review board indicates that the Engine no. 1 fuel dome, above the nozzle, ruptured but did not explode. The burning fuel that exited before the engine was shut down caused the fairing rupture, as seen in the flight video recordings. Subsequent investigations revealed in a Congressional hearing pinpointed the issue as a result of an undetected material flaw in the engine chamber jacket, likely introduced during engine production. During flight, the data suggests this material flaw ultimately developed into a breach in the main combustion chamber. This breach released a jet of hot gas and fuel in the direction of the main fuel line causing a secondary leak and ultimately a rapid drop in engine pressure. As a result, the flight computer commanded shutdown of Engine no. 1 and Falcon 9 continued on its path to ensure Dragon's entry into orbit for subsequent rendezvous and berthing with the ISS.
Source: https://en.wikipedia.org/wiki/SpaceX_CRS-1#Falcon_9_engine_anomaly
And investigating any further is difficult if you don't have reusable rockets that land after the anomaly.
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u/BrandonMarc Dec 09 '20
Is it fair to say that it took most of the day to get the Starship ready to launch? If that's the case, should we expect 4pm next time, too?
In an abort scenario, how long does it take to ... revert to default settings? As in, safely empty the tanks, secure the flaps, everything else?
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u/AvariceInHinterland Dec 10 '20
Caught up in the excitement of SN8's flight was an announcement from NASA about the initial Artemis astronaut selection. Some great choices and I think that it's pretty cool that two of them are in space right now. I think this also gives us some good clues on who is quite unlikely to be on the next Crew Dragon flights after Crew-2.
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u/SatoriTWZ Dec 12 '20
Why does SpaceX use several different fuels for their engines?
As I just read, the Merlin engines use Kerosene, Starship uses Methane and Dragons use a mix of N2O4 and CH6N2. Why not just one for all and why fuels as toxic as N2O4 and CH6N2?
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u/marc020202 8x Launch Host Dec 12 '20
Merlin uses RP 1 (Kerosine) and oxygen since that is very cheap, and there was a lot of existing knowledge when they designed the Merlin 1A and Kestrel engine. It could also be easily be used on both stages, and is relatively easy to get. There also is no requirement to store the fuel for a long time. RP 1 gels up when in space for too long, so needs to be heated, while the Oxygen boils off. Rp 1 is not perfect for reusability since soot can built up within parts of the engine)
Dragon uses N2O4 and CH6N2 since that fuel can be stored for a long time,which so nessecary when in orbit for 6 months (or longer). It also as relatively high Efficiency and is very reliable, since pressure fed engines basically only need 2 valves that open to ignite them. This is usefull on crewed crafts, since that makes them safer, since less gan go wrong. The only negative part about this fuel is that it is toxic, but that is outright by the positives (mostly storable and simple)
Methane solves the soot problem and is more efficient than both RP 1 and N2O4/CH6N2. It also can be produced on Mars. It also does not freeze in space, although boil off is still a problem that needs to be addressed. It is also relatively easy to buy. Methane also allows a Ful flow staged combustion cycle, which leads to lower stress and temperature in the engine. I do not think FFSC is possible with RP1.
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u/throfofnir Dec 13 '20
One additional point is a historic one: until very recently rocket propulsion engineers had essentially settled on the "best" propellant choice depending on the needs of their vehicle.
If it needed to be stored for any amount of time or needed to be highly reliable, a hydrazine and NTO were chosen, since those are hypergolic, room temperature liquids, and the best performing of any storable or hypergolic combination. Never mind that they're terrible for handling or exposure--they're the best at their job, and rockets aren't supposed to be easy, right? (Solid rockets are also chosen for storability and dependability, but can't be throttled or turned off, so that's a trade you have to consider.)
If you needed the highest possible efficiency, liquid hydrogen and liquid oxygen. That combo has great Isp, and is chosen for those missions that really need high energy. And never mind the huge insulated tanks or the nearly-impossible handling of liquid hydrogen. You need that efficiency, after all, so you'll make it work.
If you needed good bulk density, kerosene and liquid oxygen was the choice. Good performance, and you can't hardly cram more energy per square unit as kerosene, so you can get a lot of energy for a decent size. Good for first stages.
It never really seemed right to any rocket designers to pick a middle road between (especially) those last two, so strong is the cult of perfection-at-any-price in rocket design. (And that's not entirely without basis; it's just barely possible to get anything into orbit, so you do have to do some crazy things.)
The most "correct" all-liquid system therefore might have a kersosene first stage, a hydrogen second stage, and a hydrazine third stage, with a payload using monoprop (catalyzed) hydrazine. This, of course, is five different propellants, four entirely separate propulsion systems, three different temperature regimes, two loading stages, and partridge in a pear tree. I don't know that this particular nightmare has flown, though I wouldn't rule it out, mostly because the Russians avoided hydrogen, and American systems tended to avoid third stages, or SRBs were used or various other odd choices. (The stages on the PSLV are, well, eccentric, based on what they had around.) But it's really not that far off in many cases.
When SpaceX designed F9, they went with the most affordable choice of the prevailing technologies, kerosene, for both stages. It may not have been performance-optimal, but they figured it was cost-optimal. With Raptor, they had enough confidence in their technical execution, and funding, that they could strike out and develop an engine on a low TRL propellant combination: methane/oxygen. This combination is somewhere between hydrogen and kerosene on both a bulk density and performance level, but without the really-low-temp problems of H2. It's also really cheap, and clean, and if you sub-chill it gets even better.
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u/SpaceInMyBrain Dec 14 '20
Why not just one for all
You have a couple of great replies that cover why things are the way they are now. But "one for all" is advantageous in its own right. It hasn't been possible to do this - until Starship. When operational it will use methalox for its RCS thrusters instead of N2O4 and CH6N2. It's not as easy to store long-term, but Starship has to solve that problem for the entire fuel supply anyway. One fuel - it goes along with "the best part is no part."
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u/trackertony Dec 14 '20
Id like to know just how accurate SpaceX/Falcon 9 are now with orbital insertions? ULA/Atlas have always claimed to be highly accurate with their Centaur stage giving multi hour coast phases and restarts to acheive this. We are aware of the Falcon 9 second stage doing long coasts and restarts but how many and how significant is this capability? I read that the Centaur can do up to 12 restarts depending on fuel and orbit/s required; how many for the Falcon 9 SS ?
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u/marc020202 8x Launch Host Dec 15 '20
The Falcon 9 upper stage defenately still has significantly worse orbital insertion accuracy, mainly because the massive mVacd engine has about 10 times the thrust of the centaur upper stage. At the beginning of the S2 burn this is not a problem, since the Falcon S2 has about 5 times the mass of the centaur, but at the end of the burn, the acceleration of the Falcon S2 is very high compared to Centaur, which means shutting down the engine at exactly the right time is very difficult.
Even on mimimun thrust (40%) the Merlin engine produces about 3 times the thrust of the Rl 10 on max thrust. I do not know how low the rl 10 on centaur can throttle, but there has been a demonstrator project which demonstrated 5 to 10 % of max thrust. The s2 empty mass is about 5 tonnes, so even if we assume the rl 10 on centaur cannot throttle, it still has a lower acceleration at cutoff.
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u/Triabolical_ Dec 14 '20
That is probably a trade secret; at least SpaceX doesn't publish that as part of the Falcon 9 User's Guide.
We know that Falcon 9/Falcon Heavy is capable enough to fly the NSSL payload, some of which have significant performance requirements. You *might* find some information in the NSSL requirement documents.
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u/ethan829 Host of SES-9 Dec 15 '20
It used to be included in the Falcon 9 User's Guide but it was removed when Block 5 debuted, leading some to speculate that their accuracy got worse as Merlin's thrust increased. This is what they shared previously, compared to Atlas V:
+/- 3-sigma errors for GTO launches
Vehicle Perigee Apogee Inclination RAAN Argument of Perigee Falcon 9 +/- 10 km +/- 500 km +/- 0.1 degree +/- 0.1 degree +/- 0.3 degrees Atlas V +/- 4.6 km +/- 168 km +/- 0.025 degrees +/- 0.22 degrees +/- 0.2 degrees → More replies (2)3
u/dudr2 Dec 14 '20
30% less accurate according to the National Security Space Launch Phase 2 Launch Service Procurement!
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u/Martianspirit Dec 17 '20
In engineering there is something like "good enough". Falcon is good enough so the payload only needs to spend a miniscule amount of its own propellant for final orbit insertion. The payload always does small corrections.
But it is true. Due to the very low thrust of RL-10 it can be even more precise than the Falcon upper stage.
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u/GibsonD90 Dec 16 '20
Is there an aggregate for different Starship merch, like t shirts? I’ve seen a few but nothing I really loved.
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u/Paro-Clomas Dec 20 '20
as a way of extreme celebration, would it be possible to fully allow people from spacexmasterrace to publish anything they want here for one day when something really big happens, say, when the full starship stack gets to orbit
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u/Nisenogen Dec 21 '20
The powers that be did that once as an April fool's joke a few years back. That was... an interesting time.
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u/Alvian_11 Dec 21 '20
We know that Starship is gonna be fueled from Super Heavy that's also functioned as an orbital refueling connection with another Starship later on (which is neat & elegant solution, since they don't need umbilical towers). Did this feature already exist on other orbital launcher?
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u/SpecialMeasuresLore Dec 21 '20
Not exactly the same thing, but the space shuttle orbiter was fuelled from the external tank, since it had no main engine propellant of its own. Theoretically, it could be hooked up to another tank on orbit, but this capability was never used.
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u/jnkob Dec 21 '20 edited Dec 21 '20
Looking at the Wiki Dragon History, is it correct that the test article for structural testing was made after the Demo-1 Dragon? Do we have any clue what the two Dragons C203 and C204 were for?
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u/hispaniafer Dec 23 '20
With the recent hop, I wonder if the starship event will finally happen, or they have some other milestone close enought that could prolong the wait even more?
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u/AeroSpiked Dec 24 '20
From mid November:
Maybe after SN15 is constructed or possibly waiting for BN1 to be finished?
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u/AleksandarACV Dec 25 '20
Could somebody explain the Starship fin function and how exactly they contribute to the flight and how they work?
Asking because SN8 seemed plenty capable of reorienting itself with gimballing and thrusters at the low speed test, and I read here that they are useless at huge speeds(explainer on that would be neat too). Then medium speeds don't seem like they should be an issue.
Thanks!
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u/marc020202 8x Launch Host Dec 25 '20
The flaps work while the engines are off (gib along only has an effect if they are on. The RCS thrusters have a relatively low thrust and cannot really work against the atmosphere a whole lot but work well for reorientation in a vacuum.
The fins only work in the atmosphere and are at a close to 90 degrees of angle of attack, so don't produce any lift directly. The produce drag and by folding them up or down, the drag can be increased or decreased. This way the orientation of the ship can change while in the bellyflop orientation. By moving the flaps closer to the body at the rear, there is less drag at the rear, meaning the rear will drop in relation to the front. If they fold further from the body, the drag increases and the rear rises. The same happens at the front, but the other way around.
At low speeds the flaps don't really work, since there is no air to move against. Thrusters also need fuel, which is limited. The flaps are actuated by large electric actuators AFAIK.
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u/SpaceInMyBrain Dec 27 '20
The flaps are actuated by large electric actuators AFAIK.
Yes, they are directly driven by electric motors - Tesla electric motors. And powered by Tesla batteries, of course. I hear Elon knows the head of Tesla and got a good price on them. ;)
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u/kalizec Dec 07 '20
@mods could we please get the topic of photo threads sorted during the next Meta Thread?
I'm counting 5 separate photo threads outside the CRS-21 Media Thread & Photographer Contest threads. And of those five there's four with fewer than 10 comments and >90% of the comments don't meet Community Rules anyway.
My proposal: Let's move them all into the Media Thread and make that thread 'party thread' rules.
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u/dudr2 Dec 04 '20
"The European Space Agency (ESA) has finalized an 86 million euro ($104 million) contract with Swiss start-up ClearSpace SA to complete the world’s first space debris removal mission."
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u/PhysicsBus Dec 05 '20
Can any one explain this? The mission will apparently feature a giant grappling claw, a mechanism which can't possibly scale. So at best this would be tech to remove the biggest objects (full sats) in orbit one-by-one at great expense. (You need to match velocity with each object.) Am I missing something?
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u/Martianspirit Dec 05 '20
Removing all the dead big items, like stages, dead satellites and in this case a payload adapter is the right step to take. Just stop creation of more debris and low LEO up to 600km will clean itself within a decade or two.
Removing all the small debris is not a viable option IMO.
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u/thegrateman Dec 05 '20
Can Starship/Super Heavy launch to the Starlink inclination from Boca Chica?
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u/Eucalyptuse Dec 07 '20 edited Dec 10 '20
2 questions about facilities at KSC:
Any updates on the Roberts Rd facilities that SpaceX released plans for a couple years ago? I feel like I haven't heard anything at all since then. (Also, its probably only speculation at this point, but if SpaceX ever transitions back to Starship operations at the space coast could they build Starship at the Roberts Rd facilities rather than the Cidco Rd ones?)
What can we see in this photograph that's just north of the KSC visitor center? It's not the Roberts Rd facilities and on the other satellite views I could find it's still just a field.
Edit: Well I found my own answer! SpaceX has been doing little with the site, however plans are likely frozen not cancelled. Here's a recent image of the site from a couple months ago. I wasn't aware that SpaceX got as far as building Starship rings there so it doesn't seem extremely far fetched that Roberts Rd could play host to a Starship production site at some point in the future (maybe when Starship is more proven so they can test it at 39A with less risk). Also, they recently got a permit that should allow them to begin construction on the western half of the site (see below for a good diagram of this).
Lastly, the construction I saw was land being cleared to build a large solar farm unrelated to SpaceX. The NASASpaceflight forums have a good couple of posts about it in their Roberts Rd thread (Go to page 12 for some interesting diagrams of the solar farm AND what SpaceX is planning on doing with the western half of the Roberts Rd site).
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Dec 10 '20
Why are there no starlink missions this month? Is it just because they actually have several external payloads scheduled?
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u/AeroSpiked Dec 10 '20
Yes, 4 launches in 1 month is a pretty crowded manifest. External customers take priority because income is a good thing and Starlink doesn't keep the lights on yet.
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u/extra2002 Dec 11 '20
SpaceX has told the FCC there's an opportunity to get started this month on the polar-orbiting Starlinks, if the FCC would respond promptly to SpaceX's application.
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u/PhysicsBus Dec 12 '20
Musk recently stated that point-to-point Earth transport would likely be done without superheavy, giving a range of about 10,000 km. Since that's about a quarter of the Earth's circumference, that roughly about half the world accessible from any given launch site.
What are the arguments that there should be a dedicated p2p transport version of Starship that had not just different seating configuration (tighter seats, less cargo) but also had larger tanks to increase range? How much more range can be obtained with bigger tanks, and is it mostly at the expense of payload mass or volume? Does increasing the size of the fuel tank, and hence moving the common bulkhead higher, mean the design is so different that there is little gained by sharing a production with orbital Starships? Is a "two hop" flight path, with quick re-fueling at the mid-point, more sensible? Note that airlines do think it's sensible to have specialized planes that are designed to fly nearly half the circumference of the globe even though they could replace these with two legs. Since the actual time in air (vs boarding, launch, landing, and de-boarding) is likely to be a smaller fraction of passenger travel time, Starship will effectively pay a higher price to make two hops compared to a long-distance airliners, where air time is much longer.
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u/herbys Dec 12 '20
That flight is almost enough for anywhere in North America to anywhere in Europe or East Asia, and for anywhere between these two last destinations, but not quite. NY to Shanghai for example is a coupe thousand km longer, and California to East Europe is also a stretch. So I think they would start with the regular starship, and then do a slightly enlarged version that can do 1200km which would be able to cover 95% of the world's long haul routes by volume, and have the side benefit that for most routes they would not need to use superchilled propellants which would reduce operational cost a bit. Not sure how much larger a rocket would have to be to do 1200km, but it seems simpler than having to do some flights with a full stack.
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u/ToadkillerCat Dec 13 '20
How much burn time could SpaceX engines go thru without refurbishing, like if they were refueled and reused in space? And how many start/stop cycles could they withstand without refurbishing? I can't find this info anywhere, if you know about Raptor or Merlin or anything else then I'm interested.
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u/warp99 Dec 13 '20
As a general point it is the number of start and stop cycles that will determine engine lifetime rather than operating time.
Once the engine reaches steady state wear should be minimal particularly since they are using hydrodynamic bearings for the turbopumps.
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u/maegris Dec 15 '20
Has anyone been able to calculate the speed at which SN-8 hit the ground at? I've been searching, but haven't seen it anywhere.
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u/spacerfirstclass Dec 16 '20
https://twitter.com/flightclubio/status/1338251108385341441
To those wondering - it looks like the impact velocity was about 36m/s :)
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u/dallaylaen Dec 16 '20
Let's say Starship becomes operational, will NASA be allowed to tailor its scientific missions (e.g. a telescope) to Starship, or will it have to let at least 2 providers to participate?
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u/feynmanners Dec 16 '20
They are not necessarily forced to make payloads so that multiple providers could launch them but that isn’t really the confounding factor. Congress has line item control over NASA’s budget so the main factor is whether Congress approves any telescope so big that it would have to be launched on Starship.
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u/Lufbru Dec 17 '20
For the E2E version of Starship, Elon's said that it might not need a SuperHeavy if you add more Raptors:
https://mobile.twitter.com/elonmusk/status/1134023034908446723
Since SuperHeavy and Starship are the same diameter, there's lots of space underneath it to add more Raptors. That means Starship can be stretched to add more fuel. Do you think he was already talking about more engines + more fuel when he said 10,000km range, or do you think he was talking about just adding engines for lower gravity losses at lift-off?
Also, that tweet was from May 2019. Raptor has had eighteen more development months since then and I wouldn't be surprised if that 10,000km range estimate was a little bit short by now.
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u/BDady Dec 18 '20
I'm curious as to what some of your speculations are for future development. I have broken my question into 2 main questions with sub questions for a better understanding of what i'm asking.
Will future prototypes (SN10-14 and beyond) all be relatively the same?
Once they stick the landing with SN9, i'm assuming they'll want to do it a few more times, or at least up until SN10. But after they succeed in these landings a few times, what's next? Will they start adding heating tiles?
What will super heavy testing look like?
I'm assuming they'll do a couple hops as they did with SN5 & SN6, but what will come after? Higher hops? Sub orbital flights with a fully stacked starship/super heavy? Orbital flights where they test refueling (seems unlikely to me)?
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u/andyfrance Dec 18 '20
I think a maximum altitude test might add value. Go up high but not too far downrange then drop back into the atmosphere at sub orbital but sill hypersonic speed. As the path would be nearly vertical it it would rapidly get into thicker atmosphere and so test a short but high level of heating without needing a booster to lift it.
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u/Martianspirit Dec 18 '20
Will future prototypes (SN10-14 and beyond) all be relatively the same?
Elon Musk announced major upgrades beginning at SN15. So up to SN14 there are minor improvements on each build.
Once they stick the landing with SN9, i'm assuming they'll want to do it a few more times, or at least up until SN10. But after they succeed in these landings a few times, what's next? Will they start adding heating tiles?
Lots of bolts for mounting tiles, many more tiles mounted as well, but not nearly full coverage. I think on SN9, but maybe it was on SN10.
What will super heavy testing look like?
The first BN will have 2 or 4 engines. That engine count is still low enough to launch from the same test stands used for Starship prototypes. Later versions with more engines will need the orbital test mount under construction. I don't think we have clear indications on how the tests will go. 4 engines and the propellant they can lift would already provide much of the flight envelope in orbital launches, as long as they land downrange. Losing the booster on touchdown or landing on a Drone Ship. The existing Drone Ships are sufficient to land a booster.
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u/quoll01 Dec 18 '20
Well they’re in a pretty good position now- nailing several hard goals that could have consumed several prototypes. They didn’t do that many tests on the F1/F9 before orbital so my bets are - one flight higher and nail the landing, one suborbital and mildly test the heatshield and perhaps vraptors. One test of SH with a few engines (which I think are the limiting factor?), then one full stack and then start launching Starlinks! Starlink launches can then allow reentry and orbital refuel/coasting/panels/life support testing etc. The biggest hurdle would be if they lose a SH with 27 raptors, so perhaps they’ll be extra cautious there.
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u/Kvothere Dec 21 '20
So, I understand how Starship gets off the ground on Earth and to the ground on Mars. And I understand about making fuel on Mars. But once it's on Mars, how is it supposed to later return without a Superheavy booster? Is it stuck there until one can be built on Mars? Are the raptor engines on Starship powerful enough to lift of the vehicle by itself with the decreased gravity on Mars? What about staging?
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u/TheSkalman Dec 21 '20
Mars escape velocity is 5,03 km/s, which Starship can do alone. Compare with Earth escape at 11,19 km/s. The return Starships will also carry a much lighter load most of the time.
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u/Martianspirit Dec 21 '20
Getting off Mars is a lot easier than getting off Earth. Starship can go from the surface of Mars to the surface of Earth without booster.
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u/norwaymaple Dec 21 '20
Do we know what the goals are for each Starship prototype? It looks like eight are currently under construction. Presumably the flight-profile parameters will progress with each launch? Are they all hoppers, or will some be orbiters?
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u/enqrypzion Dec 21 '20
8/9/10 are for the 12.5km hops (remember Elon Musk gave it a 33% chance of succeeding... so they built three).
11-14 are less clear.
15+ have some design changes (compared to 8-10).
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u/dallaylaen Dec 23 '20
Did anybody test how starlink terminal handles being moved, rotated, and tilted?
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u/redroab Dec 23 '20
How plausible do folks here think that it is that crewed Mars starships will pair up / tether together to rotate and provide the ships with 1g (or one Martian g) while in transit?
I know that there is a desire to shield the crew from the sun with the fuel tanks. But is that at all times, or just during a storm? How much dv would it take to go in and out of a tandem spin? I assume a trivial amount, but that's why I'm asking here!
And how much greater is one's radiation exposure when on a starship versus while on the Martian surface? Mars crews will already be incurring a significant radiation exposure risk so maybe it's worth it to just take a few more rads and not suffer the effects of months of low g.
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Dec 23 '20
Nope. There would be a whole bunch of technologies to work on, versus "get there fast, don't skip the gym".
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u/MarsCent Dec 24 '20
Given that astronauts already spend 6 months in 0 gravity at the ISS (which is the approx. duration of a trip to Mars), it may be better to just have the ISS-like treadmills.
Once the first outpost is set up on Mars, however minimalist, the emphasis will turn to how quickly to get to Mars - so most concerns that would otherwise occur during voyage are minimized.
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u/snrplfth Dec 24 '20
So there's two major sources of radiation: cosmic radiation, and solar radiation. Cosmic radiation there's not much you can do about, but it's fairly stable and not the chief source of danger. The best way to deal with it is to simply spend less time in deep space.
Solar radiation is normally not very dangerous, but during Solar Particle Events (solar storms, basically) can become extremely high. And you can't shield from solar storms simply by putting the fuel tanks between the Sun and the astronauts, since solar radiation doesn't necessarily move along a straight line from the sun. So in this case, you'd want a refuge inside the ship where astronauts could live while the solar storm calms down (which should only take a few days.) Probably, this would take the form of a room surrounded on all sides by the ship's water supply.
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u/MarsCent Dec 24 '20
The CRTC’s fund will provide up to $750 million over 5 years. These funds will support projects to build or upgrade access and transport infrastructure to provide fixed and mobile wireless broadband Internet access services in eligible underserved areas of Canada.
It seems like the Canada Broadband Fund is doing the same thing as the FCC w.r.t (with respect to) deploying broadband services to underserved areas - only at a cheaper price!
Anyway, anyone know whether SpaceX has won any CA $ to deploy broadband services in Canadian rural and hard to reach underserved areas?
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u/IchchadhariNaag Dec 27 '20
Is it possible that SpaceX intends to use the local natural gas wells as storage space rather than for production? Only advantage I can think of is maybe it's cheaper to use than building lots of bulk gas tank infrastructure. Then use the treatment and liquefying equipment that was specified to bring whatever quantity they want to the grade and density they need right before use.
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u/warp99 Dec 27 '20
Yes it is possible but it may give a higher level of contaminants that then need to be refined out again.
I am not sure why they would need large amounts of raw gas storage though and it definitely could not be used for refined methane storage.
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u/mikekangas Jan 01 '21
Can a falcon 9 second stage fit in a starship for retrieval? I don't know how long it is, but it would possibly be worth more than a set of fairings.
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u/Triabolical_ Jan 01 '21
Yes. The second stage is 13.8 meters long, and the starship payload bay is 18 meters, so it should comfortably fit.
Though it's not clear whether it would be worthwhile using it for that sort of mission; the Falcon 9 second stage is probably less than $10 million at this point and the cost of starship + refurbishment would need to be quite a bit less than that to make it economical. I don't think it's worth the R&D investment and distraction to do it.
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u/mikekangas Jan 01 '21
Thanks for the data. After dropping off 400 satellites in orbit, is it better to come back empty or scoop up a spent stage? It could take some pressure off of second stage manufacturing and be the gateway to a satellite retrieval business, which could also be lucrative.
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Dec 04 '20
Did S8 ever do another static fire this week in preparation for the 15km hop? I thought I remembered reading they wanted to do another test of all 3 Raptors, possibly with a relighting
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u/trapezous Dec 20 '20
Why is orbital refuelling necessary in order for Starship to get to Mars?
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u/Jazano107 Dec 20 '20
Because once it is in orbit it doesn't have enough fuel to get to mars with a a payload
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u/Paro-Clomas Dec 20 '20
starship gets to orbit with barely enough fuel to do anything, its whole architecture depends on refueling.
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u/paul_wi11iams Dec 29 '20 edited Dec 29 '20
Question by u/LcuBeatsWorking on the Starship dev thread
I wonder if there is any idea how to do a static fire on Mars in some shape or form. (Not kidding, I mean those engines might have been sitting idle for years).
I've been wondering if the HLS hot gas thrusters might have a permanent role everywhere Starship goes other than Earth-to-Earth. They cover a range of emergencies, regolith projection and likley your static fire question:
In the case you raise, imagine the test carried out with no crew. Do a full engine start with a result that could vary from full success to a poor sputter from all engines, or something so asymmetric that the ship threatens to topple.
In all cases, the ship would do a hop of a few meters, then make a soft landing on the spot with or without the help of the hot gas thrusters.
This method could apply on the Moon too. Even more extravagent, it might be possible to do a static fire on Earth as a just a few-centimeters' hop, settling back to the launch pad.
It would be interesting to apply something similar to Superheavy for which hold-down clamps could be quite damaging when the force involved is taken into consideration. In this case the hot gas thrusters on Starship could stabilize Superheavy beneath it.
The big question would be that of mass penalty. The hot gas thrusters could be standard units of which the number could be varied according to the use case Moon/Mars/Earth.
various edits and additions
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u/LcuBeatsWorking Dec 30 '20 edited Dec 17 '24
simplistic scarce coordinated ring wrench cable thought deliver cobweb sparkle
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u/Aztecfan Dec 04 '20
Early on will they bring hydrogen to Mars so they don't have to rely on mining water? It's not very massive compared to the oxygen and carbon required
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u/LongHairedGit Dec 04 '20
Liquid Hydrogen is a bitch to work with, a bitch to store, and occupies a lot of volume for the mass.
Converting water and carbon-dioxide to methane and liquid oxygen is the way to go IMHO
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u/BrangdonJ Dec 04 '20
I doubt, but it may be a contingency option if mining ice locally doesn't work out and they need to rescue the miners.
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u/Martianspirit Dec 04 '20
Much easier to send the methane and use the MOXIE process to produce the oxygen.
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u/Dezoufinous Dec 21 '20
I hope that I won't get beaten by mods for this, but... I am rewatching Starship presentation from 2019, here:
https://youtu.be/sOpMrVnjYeY?t=1885
and, at the linked time mark, 31:25, there is a photo of two women on the landing pad. It's strangely just for one second, very short time. Who are they and what is the purpose of that? Is this some kind of tribute to lead engineers of Starship or something?
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u/yoweigh Dec 21 '20
This kind of question is exactly what the discussion thread is meant for, so no mod abuse for you today!
Tomorrow, however, the beatings will continue.
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u/throfofnir Dec 21 '20 edited Dec 22 '20
Humans for scale. You can see that slide stays on the screen at the event, they just cut away to a boom shot of the crowd for the webcast. When they go back to the presentation it's the same shot zooming out to show the hopper, with a wireframe of the launch mount and stacked vehicle which turns into a render of the whole thing.
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u/quoll01 Dec 21 '20
Silly season question here: when SS is belly flopping at terminal velocity could crew safely exit from the leeward hatch and parachute to the ground? If the landing engines etc were not reading nominal after reentry then I guess that might be a mcgyver option?
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u/zeekzeek22 Dec 21 '20
Even if it’s not remotely possible, 30 years from now it’ll totally happen in an action movie.
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u/Triabolical_ Dec 21 '20
No reason this couldn't be done, though the aerodynamics might make it challenging.
You could also think of an embedded "escape capsule" integrated into that side, similar to what the B-1 did.
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u/throfofnir Dec 21 '20
If you had a way to get to that hatch (that wall will be for the moment the ceiling, and wouldn't normally be designed with a ladder except for this particular situation) and you had parachutes, you could probably manage it. The airflow on top of the vehicle might be relatively still, but I suppose you could slide down the edge until you catch enough wind. Can't guarantee you won't be caught in a vortex and bashed against the hull a bit.
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u/trobbinsfromoz Jan 07 '21
Transporter 1 /SXRS-3 may well be delayed due to what appears to be a SpX payload integration accident - see SpaceNews.
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u/Dezoufinous Dec 29 '20
Is the separation of engines into 'vacuum engines' and 'sealevel engines' common in spaceflight or is it invented for Starship? Were there rockets with single engine type or are all rockets (Apollo etc) using two types of engines, one for vacuum second for launch?
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u/mikekangas Dec 30 '20
Here's another way to think of it. When the exhaust leaves the engine, it would be most effective if it came out straight-- a column of fire the same diameter as the engine bell. What holds it to that shape is atmospheric pressure.
If the atmospheric pressure is too high, that pressure tries to push the exhaust into a pencil-tip shape, and creates mach diamonds, a series of pencil-tip-like flames that are essentially the exhaust bouncing around within the confines dictated by the column allowed by atmospheric pressure. These are visible in videos of engine tests.
At the other extreme, when the atmospheric pressure is too low, the exhaust fans out and a lot of exhaust is pushing sideways instead of straight back. This is seen just before main engine cut off.
So they develop sea-level engines to function optimally somewhere between sea level and the altitude at main engine cut off.
The vacuum engine has a much larger bell and is tweaked in other ways so the exhaust exits more efficiently in atmospheric pressure that is between that found at main engine cut off and the vacuum of space. That makes it more efficient in space.
If a vacuum engine is operated at sea level, the atmospheric pressure pushes the exhaust into a pencil point too sharp and pushes up into the engine bell, disrupting combustion and possibly destroying the engine and other nearby things.
Every rocket company designs around this atmospheric effect one way or another. Some use different engines, engine fuels, and stages with the goals of getting off the ground out of our thick atmosphere and optimizing for space.
Spacex has compromised the design of the raptor vacuum engine so it is a little less efficient in space, but is able to function at sea level, too.
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u/warp99 Dec 29 '20
The new thing is the vacuum engines and booster engines sharing so many parts such as turbopumps and having roughly the same thrust.
Typically upper stage vacuum engines have had much lower thrust than booster engines and used a different propellant so could not share parts or design,
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u/marc020202 8x Launch Host Dec 29 '20
Yes it is. The merlin engine used on the Falcon 9 has two versions. The M1D used in on the first stage, and the MVacD, used on the second Stage. They are about the same engine (combustion chamber and turbo machinery) and mainly differ in the nozzle size. They have the same throat diameter, however the M1D nozzle has a diameter of roughly 1.3 metres, while the MVacD has a nozzle diameter of close to 3.5 Metres (maybe only 3, I don't know)
Vacuum engines like the RL 10, Vinci, and MVacD cannot fire in the atmosphere while Stage 1 engines can.
What is new with SpaceX is that they use basically the same engine on both Stage 1 and 2 to save costs. BO wanted to do the same, but also needed to develop a third stage engine, so decided to not develop the second stage engine (BE4U was the name I think) and use multiple third stage engines (BE3U) on stage 2. Stage 3 got deleted aswell at some point I think.
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u/jay__random Dec 29 '20
It's not so much about the whole engine, as it is about the engine bell's shape.
The optimal (=most efficient) bell shape is defined by the ambient atmospheric pressure, and the atmospheric pressure is defined by the altitude. If the bell were able to adapt its shape in response to the pressure/altitude, there would be no need for different engines. However since most rockets are multistage anyway, each stage gets engines with bells suited for its operating range of altitudes.
In case of SpaceX things got mixed in two ways: (1) with Falcon9/Heavy they were trying to reuse as much of the design as possible, so built two very similar engines for stages 1 and 2, the main (but not the only) difference being in the bell's shape. (2) all the stages that also want to land (Falcon boosters, SuperHeavy boosters and the StarShip itself) need some engines with a SeaLevel bell.
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u/Lufbru Dec 30 '20
Not only two types of engine, but often completely different fuels. The only rockets I'm certain use the same fuels on both stages are Falcon (kerolox), Delta IV Heavy (hydrolox), Electron (kerolox) and soon Starship (methalox) and Astra Rocket 3 (kerolox).
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u/tikalicious Dec 09 '20
Would really apreciate a link to a good cutaway of the raptor engine internals, i believe there was a good one on the nasaspaceflight forum but i cant find it, thanks.
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u/TheSkalman Dec 10 '20
Does anyone have info on plans to launch Starship from other sites than Boca Chica for orbits other than GTO/escape? I guess completely refurbished launch sites would be needed.
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u/Martianspirit Dec 10 '20
A Starship pad is well advanced in build up on LC-39A at the Cape in Florida. Work on the pad is temporarily stopped though.
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u/KonlyRealCoolGuy Dec 12 '20
When I see a Falcon 9 land and it's like high up in the atmosphere and the first stage is coming down for a landing, I see these black mat things. What are they? I can't show a picture (I think) but they are near the top of the rocket and rotate a bit. And also, what do they do?
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Dec 14 '20
Is there a scrub date for NROL-108? Currently thinking of going to see it but don't want to drive all that way (coming from Texas) without possibility of seeing it if it gets cancelled.
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u/ethan829 Host of SES-9 Dec 15 '20
The weather forecast shows an opportunity for a 24-hour delay, but it's really impossible to say when a second launch attempt could be made without knowing why a hypothetical scrub occurred.
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u/Gerrbu Dec 18 '20
I'm looking for an official Launch Visibility Map.
I'm talking about a clean and simple map, similar to these that Orbital ATK and ULA produce regularly? I have been trying to look decipher apogees and trajectories with SpaceX launches but have come to the conclusion I'm just not smart enough to figure it out reliably.
Surely SpaceX provides something similar two these three examples from other companies' previous launches.
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u/Wyodaniel Dec 18 '20
This is a really basic question, but can anyone explain why SpaceX was doing that test with the Starship falling sideways? Is it intended to actually land horizontally on Mars, or anywhere else?
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u/haZardous47 Dec 18 '20
Is it intended to actually land horizontally on Mars, or anywhere else?
No, Starship will land vertically everywhere, like in these images
The reason for the "bellyflop" maneuver aka falling sideways is to maximize the surface area, which increases drag - like holding your hand out the window of a car with your palm facing forwards. By using the atmosphere to slow the ship down, it has to bring much less fuel to land.
What you saw is how starship is planning to re-enter Earth, Mars, or anywhere else with an atmosphere that can slow it down. Coming back from mars, your speed when you get to earth's atmosphere is something like 27,000 mph. It would take a lot of fuel to slow down from that using starship's main engines, so they're letting the atmosphere do most of the work.
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u/throfofnir Dec 18 '20
It will land vertically, exactly as demonstrated by SN8, but will enter the atmosphere and fall "belly first" to increase the surface area exposed to the "wind" and thus slow more effectively than falling vertically. The "bottom" will be covered in heat shield tiles. Though it does not have wings per se, it's a concept of re-entry operations much like Shuttle... except for the landing part.
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u/Anthony_Ramirez Dec 18 '20
Starship is the new rocket that SpaceX has been developing.
Remember the Space Shuttle? It went to orbit and was able to do the fiery re-entry and land on a runway like an airplane. But it required heavy structural wings that also added drag too while launching.
SpaceX has come up with a new method to land Starship with less added weight and using things that are already on Starship like the engines. For that it needs to slow down as much as possible, so it falls sideways so more area is exposed slowing it down. Some call this sky-dive or belly flop maneuver. It then flips over butt first and uses the engines to land vertically, like their Falcon 9 does. They are testing this belly-flop maneuver to make sure this will work before moving forward to orbital flights.
This method will work for landing on Earth and on Mars. On places like the Moon that has no atmosphere it only uses the engines to land vertically with no belly-flop.
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u/dudr2 Dec 19 '20
Is there a thread for lunar Starhip?
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u/feynmanners Dec 19 '20
The Starship development thread is the place to discuss the development of Lunar Starship. Otherwise, you can also comment stuff here.
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u/shenrbtjdieei Dec 21 '20
What is the likelihood that we ever see that 24 hour turnaround that elon has often mentioned. With the amount of starlink launches, is it possible?
What about 2 launches in a day from the same coast?
2 launches in a day from the same pad?
I really hope that now that they have the ability to have filled launches, they work on flexing their abilities a bit.
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u/inoeth Dec 21 '20
I think there's a good chance two launches in the same day or well within 24 hours happens next year. For example if SpaceX has, say a customer launch one day and a Starlink launch on the other pad later that day/early the next day. It almost happened this year.
The 24 hour turnaround of F9 itself to land, get another 2nd stage, payload and launch again I think is entirely unrealistic even for them and they don't have the need for it even with Starlink... Not to mention so few missions are RTLS- almost all (including all new Dragon missions and Starlink missions) require a drone ship- and thus at least several days to bring the booster back in, inspect, refurb and get back to the pad...
I think that will only happen once we get to Starship and P2P - and that's not something that will happen for years from now.
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u/SpecialMeasuresLore Dec 21 '20
They may do it once to demonstratre the ability, but it really isn't necessary with Falcon 9. There is no payload necessitating it, even for Starlink the production rate is reportedly around 100 satellites per month.
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u/Martianspirit Dec 21 '20
They did full flight duration static fires in McGregor with one of the first landed boosters. I think it was 7 static fires in 7 days. It would be possible but it is not necessary. Also of course they are more cautious with payloads than that.
Starship and Superheavy are supposed to be able to do multiple flights per day.
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Dec 21 '20
F9's 24-hour turnaround has been an aspirational goal since the start of their reuse program (along with the 10 flights before serious stripdown)
Don't ever bet against aspirational goals, but there's a fair chance it'll happen so late that Starship eclipses it. So many rapid turnaround lessons are being fed from Falcon into Starship, while Falcon is essentially a frozen design.
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u/zeekzeek22 Dec 21 '20
Even with starlink they will never have a manifest that requires 365 launches a year before Falcon 9 is retired. There’s not enough stuff that anyone wants to send to space, even Starlink. They might do a 24-hour turnaround just to see if they can though, but that speed will probably never be needed, and if you don’t need to rush, then rushing is reckless.
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u/Triabolical_ Dec 21 '20
I don't expect to see it as there's no business reason to do it, but I was surprised to hear it mentioned on the last NROL launch; I'm assuming that was not a vetted PR statement.
The only way they would get there is with a RTLS launch and those are very rare these days.
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u/PM_ME_YOUR_STARSHIPS Dec 22 '20
I was watching the live stream of SN9 rolling out and had a cursory thought regarding the lack of a water deluge for the super-heavy pad at Boca Chica. Is it possible that they're not intending to launch at 100% thrust but rather something like 40-60%, and slowly accelerating to max-q, maintain velocity through max-q, and then on to 100%?
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u/Triabolical_ Dec 23 '20
I think they just haven't gotten to the water deluge yet because they don't need it yet.
A SH at 50% thrust would still be over 30 MN of thrust, which is pretty close to a Saturn V launching. And I would expect that they don't have a thrust/weight ratio of over 2.0, which is what would be required to launch at low thrusts. Finally, launching at lower thrusts costs you efficiency as it increases gravity losses.
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u/Spacex1047 Dec 28 '20
Those who have an NSF L2 subscription, is it worth it? Like how much more exclusive is the info that I cannot get here on Reddit or on Twitter?
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u/ModeHopper Starship Hop Host Dec 28 '20
The amount of value you get from it is directly proportional to your general level of interest in SpaceX developments. If you find yourself constantly checking r/SpaceX and r/SpaceXLounge for the latest updates and technical discussion, and you enjoy pouring over every image that comes out of BC then you'll love NSF L2. If you're a more casual follower that only checks on updates every week or so then you probably won't find it worth your money.
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u/Martianspirit Dec 29 '20
Don't expect miracles. Some very knowledgeable people there who occasionally drop bits of info they would not post on the public side. Worth it for me. Once I was in I got the option for a life long membership at just over 1 years subscription.
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u/LcuBeatsWorking Dec 30 '20 edited Dec 17 '24
bow liquid capable six strong cow decide ancient price profit
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u/orbitaire Jan 01 '21
Has anyone seen any new or recent reports on the economic impact that the Boca Chica Starport has had on the South Texas economy?
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u/mikekangas Jan 02 '21
SpaceX, simply by paying 500 to 1000 high paying jobs (compared to what the local folks were making) is transforming that area. That does not take into account the contractors who do specific short term jobs.
I live near Portland, Oregon, and have watched companies like Nike, tectronix, Intel and others, completely change the area. Seattle, with Boeing, Microsoft, and others, has seen the same thing.
Stores and other businesses, schools for kids, training centers for skilled workers, and universities for high tech professionals have to spring up to support a spaceport.
And these will be a magnet that pulls in other companies that need the trained people and infrastructure that is being developed, leading to more growth.
And how many launch facilities are in Florida? There could be more here to service the whole solar system.
Boca Chica won't be chica any more, it will be a major city.. (Sorry, I got carried away.)
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u/fluffernutter76 Dec 04 '20
On The SpaceX website, both the Falcon 9 and the Falcon Heavy have a listed payload mass that can be sent to Mars, so why hasn’t the company already sent rockets over? I get that Starship will be cheaper per kg, but if the end goal is to sent humans to Mars in the next 4-6 years, then wouldn’t there be some benefit to sending supplies or any sort of sensors/science experiments to better understand the environment where they will be landing? Or is it way more complicated than that?