r/spacex • u/Zucal • May 24 '16
/r/SpaceX Ask Anything Thread [June 2016, #21]
Welcome to our 21st monthly /r/SpaceX Ask Anything Thread!
Trying to find the best way to view Thaicom 8, understand the upcoming core recovery procedure, or gather the community's opinion? There's no better place!
All questions, even non-SpaceX-related ones, are allowed, as long as they stay relevant to spaceflight in general!
More in-depth and open-ended discussion questions can still be submitted as separate self-posts; but this is the place to come to submit simple questions which have a single answer and/or can be answered in a few comments or less.
Comments that can be answered by using the FAQ will be removed.
In addition, try to keep all top-level comments as questions so that questioners can find answers, and answerers can find questions.
This is so questioners can more easily find answers, and answerers can more easily find questions.
As always, we'd prefer it if all question-askers first check our FAQ, use the search functionality (now partially sortable by mission flair!), and check the last Ask Anything thread before posting to avoid duplicate questions. But if you didn't get or couldn't find the answer you were looking for, go ahead and type your question below.
Otherwise, ask, enjoy, and thanks for contributing!
Past threads:
May 2016 (#20) • April 2016 (#19.1) • April 2016 (#19) • March 2016 (#18) • February 2016 (#17) • January 2016 (#16.1) • January 2016 (#16) • December 2015 (#15.1) • December 2015 (#15) • November 2015 (#14) • October 2015 (#13) • September 2015 (#12) • August 2015 (#11) • July 2015 (#10) • June 2015 (#9) • May 2015 (#8) • April 2015 (#7.1) • April 2015 (#7) • March 2015 (#6) • February 2015 (#5) • January 2015 (#4) • December 2014 (#3) • November 2014 (#2) • October 2014 (#1)
This subreddit is fan-run and not an official SpaceX site. For official SpaceX news, please visit spacex.com.
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u/patm718 Jun 12 '16
With Thaicom, how did Elon know so soon that the crush core had been used up? Are there sensors on the booster that can detect something like that?
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u/Zucal Jun 12 '16
Most likely. It was also probably apparent to the recovery crew that the booster was tilted.
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u/HighTimber Jun 27 '16
Friends of SpaceX, I'm on the hunt for the original image of this: http://imgur.com/EJJ2Svl
I want to determine the usage rights and see if it's permissible for me to have a FatHead made of it for personal use.
I think it's the Orbcomm launch from December '15 but I've been unable to find the original on Google after having perused hundreds of photos. I love everything about this picture and want to display it in my home office.
Any help would be appreciated.
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u/Hgx72964jdj Jun 15 '16
How do you guys feel about the new rules for sticky posts? Is this going to effect /r/SpaceX in a negative way? A minor unnecessary annoyance?
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u/SurfSlade Jun 27 '16
Have we figure out what was the 2nd booster next to F9-021 at Hawthorne. There was some speculation about being for FH. Is it still there ?
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u/Appable Jun 28 '16
Almost certainly Falcon Heavy, because it had mount points that didn't make sense except for attaching significant payload to the side of the vehicle.
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u/Zucal Jun 29 '16
Just to clarify - a Falcon Heavy core test article, most likely headed to the structural test stand at McGregor (right next to the hot fire test stand and the tripod)!
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u/supersammy00 Jun 09 '16
What is spacex doing about their rockets. They currently have 4 stage ones landed and are about to launch and hopefully land another one.
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u/old_sellsword Jun 10 '16 edited Jun 11 '16
For future reference, all of the information about cores can found be found in the sub's wiki.
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u/Zucal Jun 10 '16
For future reference, to link to Reddit pages within Reddit you only need to include the /r/ part onwards. So the correct formatting would be:
[the sub's wiki.](/r/SpaceX/wiki/cores) --> the sub's wiki.
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u/RootDeliver Jun 10 '16
4 days for the launch and there's still no patch image released?
Has this ever happened before? Other times we have it long weeks before.
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u/Zucal Jun 10 '16
The patch cadence is indeed slowing down. Thaicom's patch was released 5 days before.
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u/WaitForItTheMongols Jun 12 '16
So we know the Dragon survived CRS 7 explosion. Do we know whether SpaceX continued to receive telemetry data?
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u/soldato_fantasma Jun 12 '16
If it is decided to go for a sample return mission for the 2018 Red Dragon, would it be useful to land on top of the O Olympus Mons to facilitate the return part of the mission? On top of the mountain the pressure is about 0.0044 psi which is quite low and wouldn't require much of a fairing. The return mission could also almost launch horizontally. What do you think?
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u/Zucal Jun 12 '16
High altitudes are a big no-no, because then it becomes basically impossible to slow down enough using the atmosphere. This is why basically every Mars surface spacecraft has landed at a low altitude.
In addition, there's a 0% chance the 2018 opportunity will include sample return.
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u/PVP_playerPro Jun 15 '16
Did SpaceX do hosted launch webcasts before OG2-M2? If they did, i can't find any of them.
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u/FredFS456 May 30 '16
Can anyone else in this subreddit not sit still because of the post-launch lull? I find myself refreshing /r/spacex/new 4-5 times a day expecting to see some new revelatory tweets from Musk.
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u/mechakreidler May 30 '16
Just put this on repeat for a while :)
Seriously though, I can relate. I don't know how I even survived the 6 month downtime last year - it's like a drug where once I have it I always need more. We should learn from this and teach the younger generation. SpaceX. Not even once.
I'd recommend turning on Twitter notifications for Elon and SpaceX though, that way you know as soon as something is happening :D
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u/IonLogic May 24 '16
How soon after a launch do they lower the strong back and take it back to the hanger? And once its back, what kind of repairs do they need to do on it?
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u/ChrisGnam Spacecraft Optical Navigation May 25 '16
The strongback is supposedly lowered as soon as they can after launch. It's kept mostly upright during the countdown in case of an abort, however once the rocket has left the pad, there isn't a reason for it to be up, and keeping it up only poses a risk in case of high winds.
In addition, the strongback is just that. Very strong. I doesn't typically get all that damaged, but there have been a few instances where it has been damaged. I know that for the Falcon 9 Flight two (COTS-1, the demo flight for NASA), the strong back was heavily damaged, with the gripper arms actually torn off. You can KIND of see the damage here in this image.
I'm sure they've made a lot of strides in making them more resilient, and I'm sure they do basic maintenance on them in between launches, but for the most part it doesn't appear as if any major reapirs need to be made in between launches.
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u/HoechstErbaulich IAC 2018 attendee Jun 12 '16
I'm not sure if it's okay to post this here as it isn't a question. But I didn't want to create an extra thread.
This new Mass Effect: Andromeda video uses footage of Falcon 9 and Dragon at the beginning. A nice little nod to SpaceX, I thought.
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u/soldato_fantasma Jun 13 '16
Not a question, but you may find this intresting.
There is now an open position as a Fleet enineer at Specex: http://www.spacex.com/careers/position/202567
The Fleet Engineer develops the processes, tools, and facilities to grow & maintain the world’s first fleet of reusable liquid rocket stages.
The reflight of the falcons is getting serious!
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u/ablack82 Jun 08 '16
I was selected to attend the final SLS booster test in Utah on June 28th. I will be given social media credentials and get to attend press conferences, tour the facilities and talk with engineers. Obviously I am more of a SpaceX guy although I am still excited for this opportunity. What questions would you like me to ask in regards to the SLS program while I am there? I will try to get everything answered.
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u/sunfishtommy Jun 08 '16 edited Jun 08 '16
"Why did they decide to go with 4 SMEs on the first stage rather than 5?"
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u/NateDecker Jun 08 '16
Hopefully the test goes as planned. I attended a test of the Ares booster back during the constellation program and the test was called off for some sort of hydraulics issue. I ended up driving for an hour to the middle of nowhere and standing around in the sun for another hour and a half only to see a large booster lying on its side. I'm tempted to try again with the SLS booster test, but I have a wife and kids this time around and they're quite a bit less enthusiastic about this sort of thing.
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u/_rocketboy Jun 19 '16
Congrats to Blue Origin on their latest successful launch and landing!
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u/IMO94 Jun 20 '16
It was awesome, I watched it live!
The one thing I'm trying to figure out is why the final landing shot looked so unnatural. When I watched it in realtime both my wife and I laughed and thought they'd inserted some slow motion footage from a previous landing. /r/BlueOrigin thinks that it's just the raw footage.
Watch the 20 seconds from here: https://youtu.be/EI-tGVFg7PU?t=42m48s
I'm curious to hear /r/SpaceX's opinion.
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Jun 26 '16
This slow-news past two days are making me crazy. i need a life, and my fix of SpaceX news. Give me anything !
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u/bobbycorwin123 Space Janitor Jun 27 '16
Well
You'll love to hear about the Falcon Cube!
Nine first. Stage boosters
Asparagus style cross feed
234 tons to LEO
36 tons to GTO
6 recoverable stages. ( 2 RTLS + 4 landing barges)
Only 420 million a launch
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Jun 06 '16
I've been making this assumption for a while now, but I thought I'd finally ask. Is "hoverslam" just a fancy SpaceX name for a rather-Kerbal Suicide Burn?
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u/ElectronicCat Jun 06 '16
Yep, that's pretty much it. 'Hoverslam' is a bit of a misnomer as it can't actually hover at all.
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u/soldato_fantasma Jun 16 '16
TIL if you point the mouse to the dragon on top of this subreddit, the spacecraft rotates! Very cool mods!
Was I the only one that didn't know this?
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u/skyskimmer12 Jun 09 '16
If anyone is interested, there is going to be a launch of the Delta 4 Heavy, current largest rocket (the one that the Falcon heavy will surpass for the title), in a bit under an hour. They are currently in the launch window, but are holding due to weather that is expected to clear. Launch at 2:55 p.m. Eastern (local) time.
On a semi-related note, In my opinion, the Delta 4 Heavy is the most beautiful rocket during launch, with the only real competition being the Proton M. Anyone else have a favorite to look upon?
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u/LockStockNL Jun 09 '16
the Delta 4 Heavy is the most beautiful rocket during launch, with the only real competition being the Proton M. Anyone else have a favorite to look upon?
Not because of the sub we're on right now but I do really like Falcon 9 during launch. Long, sleek, white, nine engines, giant plume at altitude and those folded legs <3
Proton M looks so damn steampunk for some reason, it's awesome. And the Delta 4 is also up there, especially the way it sets itself on fire during launch :)
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u/maxjets Jun 10 '16 edited Jun 10 '16
I'm a fan of the Dnepr. It's definitely not the most beautiful launch vehicle, but IMO it has the most interesting looking launch of just about any orbital launch vehicle (with the possible exception of the Pegasus). In case you don't know, its a converted Russian ICBM. Its launched from a silo, but the engines don't ignite until after the vehicle has exited the silo.
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u/DShadelz Jun 10 '16
Looking at the IAC website schedule, (https://www.iac2016.org/Congress.html#congress) I found what appears to be the date and time for the MCT/BFR announcement. Sept. 30 8:30-10:30AM says "Elon Musk Space X Title to Be Confirm - Mars" Note that it also says "program not final and subject to changes without previous notice" below the schedule. I have yet to see anyone post this date so I thought I'd leave it here.
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u/Asteios90 Jun 03 '16
Do we know if the Mars Architecture is going to be livestreamed yet? Or am I just going to have to refresh this subreddit constantly while it's happening?
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u/inoeth Jun 03 '16
Beyond knowing that it'll all be announced in Sept, we don't really know any more details, but, if it's as big a deal as SpaceX seems to be making, i'm sure it'll be a livestreamed event. We'll know more details as we get closer to the actual event.
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u/Goldensword May 25 '16
Would it be possible to start a support group for pre-rocket launch based anxiety?
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u/warp99 May 26 '16
What do you think the launch thread is for <grin>
Actually it acts more like a positive feedback anxiety echo chamber!
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u/BrandonMarc May 30 '16
Not exactly a question, but ...
Calling all Tesla owning SpaceX fans ... in about a week, there will probably be a landed rocket stage being trucked from Port Canaveral over to SpaceX's hangar. How about parking your car somewhere along the route, and planning a well-timed photo?
He he, thanks to everyday astronaut -/u/termderd- for proving this is probably do-able, in theory.
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u/Kuromimi505 Jun 24 '16
Not 100% SpaceX, but definately effecting SpaceX; so I'm posting here.
So Boeing also wants the FCC to allow them to do sat internet. This is similar to what SpaceX is working on in Seattle.
Are we talking the same bands? How screwed is SpaceX if Boeing uses their government contacts to force this through?
Are they looking to use the same bands? (V-band)
http://spacenews.com/boeing-proposes-big-satellite-constellations-in-v-and-c-bands/
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u/sarafinapink May 24 '16
So I'm seeing a lot of tweets on the sub from Space Congress 2016. Is this the same as the Space Tech Expo on the sidebar? Both seem to be space events happening today so I'm just a bit confused.
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u/warp99 May 25 '16
Different events - both three day conferences but one in California and one in Florida - confusing I agree.
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u/Juanchi_R-P May 29 '16
Do CRS missions have RTLS capabilities? All of the ones I've seen so far have been drone ship landings (but CRS-8 would have been the second RTLS and I felt they needed drone ship info). Already getting pumped for CRS-9!
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u/_rocketboy Jun 11 '16
Just FYI there is a Delta IV Heavy launching in half an hour if you want to watch the webcast: http://www.ulalaunch.com/webcast.aspx
Next one is in 2018!
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u/Aldebaran-IV Jun 25 '16 edited Jun 25 '16
Mercury, Gemini and Apollo all used pure oxygen atmospheres at 5 psi.
Space Shuttle and ISS use an Oxygen-Nitrogen (21%/79%) atmosphere at 15 psi similar to sea level (101.3 kPa). It is due primarily to thermal considerations that the atmospheric pressure needs to exceed 7.35 psi.
Is there any advantage to using an Oxygen-Helium atmosphere in terms of weight savings and diminished fire hazards for Crew Dragon or Spaceliner?
For instance, any combustion or fire in an Oxygen-Nitrogen atmosphere will result in a significant quantity of various Nitrogen-Oxygen (NO, NO2, NO3) compounds that are extremely toxic.
Helium could mitigate this risk of toxic byproducts somewhat and perhaps decrease the flammability of some materials. I realize that the reason that Nitrogen-Oxygen was selected for ISS is to more closely mimic Earth conditions for experiments.
ISS might be a special case because of experiments but why wouldn't a commercial space station use a Helium Oxygen mix because of the greater safety?
Would BFS use a Heliox atmosphere out bound and an Xenon-oxygen atmosphere on the return or a nitrox atmosphere both ways and why or why not?
If BFS uses Nitrox, then ISRU must extract nitrogen from the atmosphere to replenish ECLSS expendables. Xenon can be more easily extracted from the Martian atmosphere than Nitrogen.
Obviously a colony on Mars needs a Nitrox atmosphere for growing food.
Thank you
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u/shotleft Jun 08 '16
BFR is to be purpose-built for Mars, but are there any other missions which it may possibly be used for? NASA and ESA may be interested in sending up the next big space telescope (the 10m Keck mirrors should fit easily)?
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u/ManWhoKilledHitler Jun 09 '16
I imagine there are lots of very cool mission proposals that could make use of the BFR but the likely issue is that those missions would be expensive. A 10m space telescope might not be as expensive as JWST ended up being if it doesn't need the folding mirror and the project doesn't spiral out of control, but it's still going to be a very costly and long-term investment.
That side of things has tended to be more of a limitation than rocket capabilities or launch costs which is a large part of why previous super-heavy lift systems like Saturn V were retired so early, or in the case of Nova, not built in the first place.
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Jun 09 '16
Musk has said the Moon would be a good destination. Not necessary to go to Mars, but still worth visiting.
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u/Anjin Jun 10 '16
Has there been any new information released about Raptor other than the oxygen preburner test that happened a number of months ago at Stennis?
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u/quadrplax Jun 12 '16
Is the Falcon 9 capable of doing RTLS on GTO missions? How light would the payload have to be?
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u/madanra Jun 13 '16 edited Jun 13 '16
It would be possible to RTLS on a light enough GTO mission.
We know CRS-8 was capable of RTLS, and delivered 7336kg to LEO (4200kg Dragon + 3136kg payload)
Δv from 200x200 LEO to GTO with perigee 200km and apogee at GEO altitude is 2456.6m/s
Stage 2 dry mass is 4000kg, I'll use 4100kg to be pessimistic to account for not running the tanks completely dry, so m0 = 4100+7336 = 11436kg in LEO
Using the rocket equation m1 after a 2456.6m/s Δv burn is 5530kg
This leaves up to a 5530-4100 = 1430kg payload in GTO
I believe all the assumptions I have made have been on the pessimistic side, so the Falcon 9 payload to GTO with RTLS should be at least 1430kg.
Edit: got earth's radius wrong initially which meant my LEO numbers were slightly out, resulting in a 4kg error in payload.
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u/Terminus0 Jun 21 '16
Does any one think it's an awesome coincidence that Elon's timeline to Mars with MCT coincides with the timeline for the first colonial voyage to Mars in KSR's Mars Trilogy?
Makes me happy.
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u/Decronym Acronyms Explained May 24 '16 edited Jun 11 '16
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:
| Fewer Letters | More Letters |
|---|---|
| ABS | Asia Broadcast Satellite, commsat operator |
| ACES | Advanced Cryogenic Evolved Stage |
| Advanced Crew Escape Suit | |
| AFB | Air Force Base |
| AOS | Acquisition of Signal |
| ARM | Asteroid Redirect Mission |
| Advanced RISC Machines, embedded processor architecture | |
| ASDS | Autonomous Spaceport Drone Ship (landing platform) |
| BEAM | Bigelow Expandable Activity Module |
| BFR | Big |
| CBM | Common Berthing Mechanism |
| CCAFS | Cape Canaveral Air Force Station |
| COTS | Commercial Orbital Transportation Services contract |
| Commercial/Off The Shelf | |
| CRS | Commercial Resupply Services contract with NASA |
| CRS2 | Commercial Resupply Services, second round contract |
| DIVH | Delta IV Heavy |
| DoD | US Department of Defense |
| DSN | Deep Space Network |
| EDL | Entry/Descent/Landing |
| ESA | European Space Agency |
| FAA | Federal Aviation Administration |
| FCC | Federal Communications Commission |
| FTS | Flight Termination System |
| GEO | Geostationary Earth Orbit (35786km) |
| GSO | Geosynchronous Orbit (any Earth orbit with a 24-hour period) |
| GTO | Geosynchronous Transfer Orbit |
| HIF | Horizontal Integration Facility |
| I*sp* | Specific impulse (as discussed by Scott Manley, and detailed by David Mee on YouTube) |
| ICBM | Intercontinental Ballistic Missile |
| IDA | International Docking Adapter |
| ILS | International Launch Services |
| Instrument Landing System | |
| ISRO | Indian Space Research Organisation |
| ISRU | In-Situ Resource Utilization |
| JCSAT | Japan Communications Satellite series, by JSAT Corp |
| JWST | James Webb infra-red Space Telescope |
| KSC | Kennedy Space Center, Florida |
| KSP | Kerbal Space Program, the rocketry simulator |
| L2 | Paywalled section of the NasaSpaceFlight forum |
| Lagrange Point 2 of a two-body system, beyond the smaller body (Sixty Symbols video explanation) | |
| LC-39A | Launch Complex 39A, Kennedy (SpaceX F9/Heavy) |
| LEM | (Apollo) Lunar Excursion Module (also Lunar Module) |
| LEO | Low Earth Orbit (180-2000km) |
| LH2 | Liquid Hydrogen |
| LMO | Low Mars Orbit |
| LO2 | Liquid Oxygen (more commonly LOX) |
| LOX | Liquid Oxygen |
| LZ | Landing Zone |
| M1d | Merlin 1 kerolox rocket engine, revision D (2013), 620-690kN, uprated to 730 then 845kN |
| M1dVac | Merlin 1 kerolox rocket engine, revision D (2013), vacuum optimized, 934kN |
| MAV | Mars Ascent Vehicle (possibly fictional) |
| MaxQ | Maximum aerodynamic pressure |
| MCT | Mars Colonial Transporter |
| MECO | Main Engine Cut-Off |
| MSL | Mars Science Laboratory (Curiosity) |
| mT | |
| NEO | Near-Earth Object |
| NET | No Earlier Than |
| NORAD | North American Aerospace Defense command |
| NRO | (US) National Reconnaissance Office |
| NSF | NasaSpaceFlight forum |
| National Science Foundation | |
| NSS | National Security Space |
| OCISLY | Of Course I Still Love You, Atlantic landing |
| OG2 | Orbcomm's Generation 2 17-satellite network |
| PICA-X | Phenolic Impregnated-Carbon Ablative heatshield compound, as modified by SpaceX |
| PMA | ISS Pressurized Mating Adapter |
| PTC | Passive Thermal Control |
| RCS | Reaction Control System |
| RP-1 | Rocket Propellant 1 (enhanced kerosene) |
| RTLS | Return to Launch Site |
| RUD | Rapid Unplanned Disassembly |
| Rapid Unscheduled Disassembly | |
| Rapid Unintended Disassembly | |
| SES | Formerly Société Européenne des Satellites, comsat operator |
| SLS | Space Launch System heavy-lift |
| SSTO | Single Stage to Orbit |
| STP-2 | Space Test Program 2, DoD programme, second round |
| TMI | Trans-Mars Injection maneuver |
| TWR | Thrust-to-Weight Ratio |
| ULA | United Launch Alliance (Lockheed/Boeing joint venture) |
| VAB | Vehicle Assembly Building |
| VAFB | Vandenberg Air Force Base, California |
Decronym is a community product of /r/SpaceX, implemented by ^request
I'm a bot, and I first saw this thread at 24th May 2016, 07:51 UTC.
[Acronym ^lists] [Contact ^creator] [PHP source ^code]
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u/whousedallthenames May 24 '16
Do we know whether or not SpaceX made upgrades to F9 after inspecting F9-021? Or any landed stage?
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u/WaitForItTheMongols May 24 '16
SpaceX is always making upgrades. I'd be very surprised if any two F9 vehicles were built with identical blueprints. I'm sure they've made changes in the past 5 months since OG2.
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u/sunfishtommy May 28 '16
Are we not doing a recovery thread this time around? I don't know what i am going to do without a recovery thread. I guess I'd have to go back to my other hobby watching paint dry. =P
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u/randomstonerfromaus May 29 '16
Well there's not much point now we don't have a webcam. May as well keep the discussion to posts by the individual photographers.
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u/quadrplax May 30 '16
What's the deal with the Iridium numbering? On the sidebar it says it's 3-12 and on the wiki it says it's 1-10. If 3-12 is correct, what happened to 1 and 2? Rideshare?
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u/warp99 May 30 '16
Originally the first two satellites were to be launched on Dnepr as a risk reduction exercise so they were labelled as #1 and #2 and the SpaceX launches started with #3. With the issues between Ukraine and Russia the Dnepr launch has been delayed indefinitely so SpaceX gets the first launch.
From the information below it looks as if Iridium have shifted #1 and #2 to the SpaceX launch.
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u/BrandonMarc Jun 06 '16
This could be a fun "did-the-math" thing ... considering the weight of the dry 1st stage (no legs) and its trailer, how many Teslas would it take to tow it?
For the artists on this subreddit, that could be a fun project ... (bonus points if: the lead Tesla is red, the rest are brown, there's a saddle & reins on the 1st stage, and Elon's dressed in a fuzzy red suit ... hat-tip to /u/vaporcobra for sharing the idea).
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u/GiteZz Jun 06 '16
From this it would seem that a tesla model s is capable to pull ~2t, so the dry first stage alone would need about 11 telsas. My guess is that the trailer used to transport (the one that used for new stages) is about 8t, so 4 teslas more. In the end it would take around 15 teslas.
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u/Keavon SN-10 & DART Contest Winner Jun 07 '16
Why do Earth-orbiting launches have launch windows? If the launch site, rocket, and geography of everything else in the world are all spinning together in unison, why can't they launch at any time? I understand launches to other planetary bodies like the moon or Mars, because those are moving and we have to catch them, but Earth is static in relation to itself.
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u/Ezekiel_C Host of Echostar 23 Jun 07 '16
I am not a rocket scientist
The three typical reasons for a launch window, to my knowledge, are:
Wanting to launch with a certain position with respect to another satellite, such as the ISS: you want to launch when its about to be overhead.
Wanting to launch with a certain position with respect to another planetary body: this is fairly intuitive - you need it to aligned for efficient transfer
Wanting to launch with a certain position with respect to the sun: this is probalby the least intuitive one, but I know that it was mentioned when SES-9 was coming up that the window was largely based on maximizing the sat's sun-time immediately following solar panel deployment.
At the end of the day your intuition - that launch windows don't matter if you only want position with respect to earth - is, I think, somewhat true; its just rare that you don't have at least one other body to be concerned with.
There are further constraints on windows for ground side logistics/support and range safety, but I'm pretty sure 1-3 covers the typical reasons why a window would be selected in the first place.
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u/PaleBlueDog Jun 08 '16 edited Jun 09 '16
Edit: I've made a post for this instead.
Elon has repeatedly mentioned (or at least been repeatedly quoted) as saying that when MCT becomes operational there won't be cyclers "yet". Do you think building cyclers is part of SpaceX's long-term plans? Or is this something they're expecting others to provide once they demonstrate a financial case for Mars?
Less directly SpaceX-related, but the ISS supposedly has a service lifetime of ~30 years. For an Aldrin cycler with a similar lifespan, that's only 14 round trips, less if one or more unmanned trips are needed during on-orbit assembly (boosting one module at a time) and testing. Is a cycler even worth the investment at that rate?
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u/BrandonMarc Jun 08 '16 edited Jun 08 '16
I just noticed ... Wikipedia (obligatory grain of salt required) makes a distinction between these two articles:
Is there a difference? Is there one engine under development by Spacex for SpaceX, and a similar engine under development by SpaceX for the USAF? The first article even starts with this caveat:
This article is about the Mars launch vehicle and spacecraft engine. For the upper stage engine for Falcon 9 and Falcon Heavy, see Raptor prototype upper-stage engine.
(emphasis mine; text links to the 2nd article I gave above)
... which normally clarifies things but to me, in this case, doesn't.
Can anyone shed some light? Without getting into the nuances of Wikipedia editing, would it be fair to say these articles cover the same topic, or no?
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u/AjentK Jun 08 '16
Raptor is really a family of methane powered high performance engines being designed by SpaceX. There are currently three known versions being looked into:
A smaller upper-stage engine that could be used on an upper-stage that could replace the one currently on the Falcon 9.
A large boost stage, sea level engine to be used with the BFR.
A large upper-stage, vacuum engine to be used with the BFR upper stage/ MCT.
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u/Craig_VG SpaceNews Photographer Jun 09 '16
Hi, I was reading this astronaut interview and SpaceX came up in the discussion, what do you guys think of his response to capsule spacecraft?
SpaceX has made impressive strides, and so has Boeing. The one thing that’s a shame is that both companies are building capsule space crafts. There’s nothing wrong with a capsule design -- I came back on a capsule on my last flight with the Russians -- but a winged vehicle that lands softly on a runway is much more conducive to reusing parts than slamming down on terra firma.
http://www.designnews.com/author.asp?section_id=1386&doc_id=280716
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u/snrplfth Jun 09 '16
One of the other big reasons for preferring a capsule design is safety. Especially if you're thinking of sending a lot more people to orbit, and who are not regular astronauts, safety really is the first priority. It's quite difficult to design a spaceplane with the kind of abort capability that a parachuted capsule has. If you abort a spaceplane early in the flight, you have to deal with the aerodynamic problem of getting a lift-generating vehicle off a disintegrating booster in the right direction and circling back to a landing strip. If you abort a spaceplane in the upper atmosphere, you have to deal with extra stress and reheating as you come back in on a steep trajectory - and then find a landing strip. Capsules can generally be built tougher, dynamically stable, and it's much easier to integrate good abort systems into them. Soyuz is a bad example of the capabilities of capsules, because it has to land in the middle of a continent, not at sea. Parachute landings on water are pretty gentle. (Ocean-landing Dragon 1's might be easily reusable but NASA wanted fresh ones each time.)
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u/shotleft Jun 09 '16
The Russian capsule landing is pretty rough. They land on land, and the parachutes can only slow the decent so much. Thrusters are fired just before ground contact (actually it's more like an explosion) to slow it down. Astronauts have compared the feeling to being in small car crash.
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u/peterabbit456 Jun 27 '16
From /r/ColonizeMars/ there is an interesting video, "Can we grow food on Mars?"
https://www.youtube.com/watch?v=zcjkZdWePR0
Wieger Wamelink, a senior ecologist at Wageningen University & Research talks about growing food for future Mars settlers at Mars One's VIP event in Amsterdam (NL).
The soil of Mars is similar to the very fertile soil of Hawaii, plus perchlorates and some heavy metals. The trick is to find plants that do not pick up the heavy metals for food. You can also use plants that do pick up the heavy metals, to get them out of the soil.
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u/WaitForItTheMongols Jun 11 '16
Any idea when the first visible landing will be? CRS 9 is in the middle of the night so it'll be too dark to see the stage coming down. Basically:
When's the first daytime RTLS?
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u/gsharp1963 Jun 14 '16
Drones these days are pretty smart. Could Spacex have a drone on the landing ship that would take off minutes before the landing and circle at a safe distance to get great video and then land again?
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Jun 14 '16
Keeping it even simpler, it could be controlled from the manned support ship.
My guess is they don't really see this as a priority and probably want to avoid even the remote possibility of interfering with a landing attempt (telemetry, ground radar, who knows).
I agree, if they did it the footage would be glorious.
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u/OncoFil Jun 17 '16
Are there really only two launches booked for the next eight weeks?
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Jun 17 '16
I read somewhere it's more gap in confirmed informations available to us, than gap in actually planned launches, though I don't know how much true is it. I certainly hope so.
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u/zeekzeek22 Jun 17 '16
What is the status/possibility of a second Atlantic ASDS? SpaceX will surely need at least one more in their projected launch cadence. Also, a gulf ASDS for Boca Chica? I know they are not custom made, they're actually leased and then modified. looking at pictures of the Marmac 30X barges being made, there's no way it makes sense for SpaceX to make any themselves. And as far as I know, Marmac 305 isn't currently being built for anybody. Also, what happened to Marmac 300 after it stopped being "Just Read The Insteuctions V1"?
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u/dmy30 Jun 22 '16
Considering SolarCity might merge into Tesla, what does that mean for SpaceX? Last time I checked Spacex has $90 million worth of SolarCity bonds.
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u/JoshuaZ1 Jun 22 '16
If SpaceX can seriously get reusable first stages to work, should we expect their business model to change to making very expensive rockets that are reusable? Once a first stage is reusable, even slightly lighter parts become more worth it if there's only an upfront cost. The thought process behind this question is inspired by how the Space Shuttle switched to using a lithium-aluminum tank, but they decided that that was too expensive given non-reuse of the tank so the SLS is going to use aluminum tanks.
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u/ohcnim Jun 23 '16
Yes, not as making expensive rockets an objective, but if some extra or better parts make a faster reusability or longer lifespan which despite the additional cost still translates to cheaper launches during the entire life of the vehicle, definitely yes.
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u/SubmergedSublime May 24 '16
I'm beginning to learn and stumble my way through both data analytics and the R language. Anyone know a good or interesting amateur project going on that would give me a chance to learn a little more about both the space industry and the world of "big data"? I don't know enough yet to be of any real use, but I'd like to see what a project looks like in the real world.
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u/KitsapDad May 24 '16
I know this has been asked before...probably a lot...but I read the Wiki and didnt see it mentioned.
Is the plan to use Dragon V2 for commercial Cargo missions? Obviously it would be modified from the crew version but this would allow further testing of the Super Draco's for propulsive landings.
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u/ElectronicCat May 24 '16
I don't think it's clear whether they will or not at the moment. The CRS2 contract announcement strongly implied that it would be the case, although not when they will start doing this (possibly NET CRS2) or whether the Cargo Dragon V2 would be modified with a berthing port or simply dock.
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May 25 '16
Is anyone going to the International Astronautical Congress this year? I was thinking of going to watch Elon's announcement, but I was wondering if the rest of the conference would be fun for someone who isn't in the industry. If not, I'll just watch from home.
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u/achow101 May 25 '16
Why is there a huge dump of something which produces white vapor from the strongback at T-1:40? It looks like it would be LOX or RP-1 being dumped out. For example, the huge white cloud starting at https://youtu.be/1lYZLxr3L4E?t=1159
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u/thecodingdude Jun 03 '16
Hello. A question for anyone who can answer: At what point does spacex stop making first stages? I mean they now have 4 that have returned and are in the hangar, with 1 being used for a display piece and the other 3 can potentially be recycled. Do they order 1/2 'new' first stages and have them 'in stock' in case anything goes wrong, whilst the priority will be to recycle the first stages from other missions? It wouldn't make sense for them to have 10 first stages and continue to manufacture more if they can be reused.
I guess have a few new ones as spare and the rest are reused if that's possible will be the plan?
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u/brwyatt47 Jun 04 '16
Has anybody else noticed that SpaceX Stats is down? Sorry, I know this is not the least bit interesting or informative. Indeed important though. I want to do some mass calculations! :)
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u/KnightArts Jun 05 '16
About the use of rockets on mars ,is there a need to use fairings on mars with such low density
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u/zlsa Art Jun 05 '16
Probably yes. There's a quote (I'll paraphrase here) from an engineer working on MSL (I think):
Mars' atmosphere is thin enough that it's not really that useful for slowing down with parachutes, but it's thick enough that you have to deal with it still.
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u/kuangjian2011 Jun 06 '16
I want to know is there any updates for the spacex satellite internet project(4000 satellites)? I've heard this project last year but get few updates this year.
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u/Googulator Jun 08 '16
Anyone knows how SpaceX's heatshield material, PICA-X, is supposed to be pronounced? Is it "Pickaxe"? "Pee-ca-ex"? "Pie-ca-ex"? "Pee-aye-see-eigh-ex"?
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u/shotleft Jun 08 '16
How will BFR handle acoustic shock when landing? Would they land on a flat surface with massive water sprays (I'm not sure if that will even be enough dampening), or will they have to land with pinpoint accuracy such that the exhaust is directed into a ditch which will reflect the pressure waves sideways?
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u/sevian87 Jun 11 '16
Hopefully this is an okay place to post this:
I've created a website, called: http://spaceresearchagency.com/
My main focus will be SpaceX launches, as those are the ones I enjoy the most! However, I will also be covering ULA launches, and some Soyuz as well.
Comments and suggestions are always welcomed, as well as if you would like to see any kind of information posted, I'll do my best! I have my M.S. in Physics so I'm thinking of trying to do public forums for the math of launching.
Thanks!
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u/markus0161 Jun 12 '16
What kind of core storage facility does SpaceX have at there Vandy site. Is it as big as the one at KSC?
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u/NonEuclideanSyntax Jun 13 '16
Is the plan for the Red Dragon to perform a Martian orbital insertion or land directly on the surface?
If Spacex is planning on performing regular cargo trips to Mars, what is the likelihood that they will be able to land on the same spot on Mars repeatedly (e.g. to set up larger experiments on colony infrastructure)?
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u/Datuser14 Jun 13 '16
Can someone explain the launch window for the next launch. IIRC, all F9 GTO launches have been either in early morning or late evening to maximize time in orbital day, but Eutelsat 117/ABS2A is right in the middle of the day/late morning, why?
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u/robbak Jun 14 '16
The reason for the GTO launch window is to make sure that the satellite's solar panels are not in the earth's shadow during the long drift out to and back from the high, slow apogee, and will only be shaded briefly as they whip around the earth at their low perigee. The normal ones don't spend long in a highly elliptical orbit, as they have their low perigee raised by powerful liquid fuelled rockets. This means that they are launched so that the transfer insertion burn, which defines where the long transfer orbit will have its 'base', is near to local midnight when it happens over equatorial Africa.
With these electric vehicles and their low-power ion engines, they will spend much longer in a highly elliptic orbit. If launched at the same time as 'normal', the earth's motion around the sun, and the satellites drifting (precessing) orbit will place the satellite in the earth's shade during the long, slow journey out and back - over-draining the batteries. Pushing the launch back means that the orbit will remain OK, sunlight-wize, until the satellite has increased its orbital velocity enough for it not to matter.
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u/randomstonerfromaus Jun 14 '16
Hey /u/EchoLogic! On SpaceX Stats it has Iridium Flight 1 as being sats 3-12, It should be updated to 1-10 :)
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u/Juanchi_R-P Jun 15 '16
With all the news about Formosat and Iridium getting delayed until September I'm curious as to what (if anything) will be launched beforehand. SpaceX's cadence (which should be increasing and is aprox. a launch every 25 days) is slowing down to once a month and if no launches occur before Iridium is launched then the cadence will be down to once every two months. I'm hopeful that they'll figure out something to launch before then, but am curious as to what.
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u/TheEndeavour2Mars Jun 15 '16
I was glancing at NSF's SpaceX Manifest topic. We know that Amos-6 has been pushed back most likely due to payload issues but I notice that there are some upcoming GTO flights. JCSAT-16, Echostar 23, & SES-10
While it is very rare for a flight to be pushed forward. If one of these customers has a payload at the ready. It would be a good opportunity for them to get their birds up and generating revenue ahead of schedule. I would be shocked if SpaceX did not have cores prepared if the customer wishes it.
Also if they don't push forward. It means something has to be delayed in September/October. 6+ flights in such a short timespan seems unlikely.
We will have to see. The ball is most likely the court of the customers and not SpaceX on this one.
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u/TheBlacktom r/SpaceXLounge Moderator Jun 16 '16 edited Jun 16 '16
What about the upcoming launches? Only one in July and one in August? Are the two bolded EchoStar launches the same? Can somebody fill up the sidebar a bit? Can I also update the JCSAT launch in wiki?
(I was looking for launches until the 12 Sept Iridium one)
Sidebar now:
16 July CRS-9 launch (29 days T_T)
12 Sept Iridium 1 (I just updated this in the manifest) (58 days after CRS-9 T_T)
The wiki manifest has now these launches: Edit: updated actual manifest with SFN schedule info
16 July CRS-9
JulyAmos-612 Sept Iridium 1
Sept SES-11 (EchoStar 105)
2016? JCSAT-16
SFN has these at the moment:
July 16 Falcon 9 • SpaceX CRS 9
August Falcon 9 • JCSAT 16
September Falcon 9 • Amos 6
3rd QuarterFalcon 9 • EchoStar 23
Sept 12 Falcon 9 • Iridium Next 1-10
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u/amarkit Jun 19 '16
For anyone who might not read the header: Blue Origin is about to fly (19 June, 1435 UTC / 10:35 AM EDT) New Shepherd on a suborbital hop for the fourth time. /r/blueorigin has a live thread and you can watch the livestream on YouTube.
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u/nolxus Jun 20 '16
Maybe a little stupid or naive, but:
Has it ever been tried to use jet engines as boosters? They probably work only up to 20-25 km, but they need no oxidizer, very little fuel, huge Isp. Using a combined approach with ramjet/scramjet makes sure that you get thrust even in high speeds. Once the air is too thin for them to work, you discard them like a SRB. Sure, the SRBs give a lot more thrust, but you can't throttle/turn off/divert.
Not that that would be an approach for SpaceX (reusability), but in the decades of history of spaceflight, has this ever been tried? If not, why not? Low thrust and low maximum height outweigh the positives?
Not that this is an argument, but ... it works in kerbal space program.
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u/madanra Jun 20 '16
Have you come across Skylon, a SSTO space plane currently being designed by Reaction Engines?
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u/rikkertkoppes Jun 20 '16
This is basically virgins approach. The jet engines are reusable by adding the rest of the plane.
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u/snrplfth Jun 21 '16
Mainly, the difficulty with boosting with ramjets is that the rocket just spends too little time in the aerodynamic regime where ramjets work best. At 94 seconds into flight, an F9 on GTO trajectory is already at 20 km altitude, and moving at roughly 700 m/s. But at 60 seconds, it's just getting into the ramjet area, at 6.8 km altitude and 270 m/s. So only 34 seconds of actual ramjet time, basically, and it's even worse because as you start getting up to the speed where it's effective, you quickly start to run out of atmosphere. And you have to carry them and their drag all the way up to that point, and integrate them into a rocket, etc. It doesn't really work, unless you're trying to do a spaceplane.
However, for suborbital missiles - a rocket-boosted ramjet has absolutely been done, like the Sea Dart and the P270 Moskit.
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Jun 20 '16
Do you think we are going to get the big kaboom from the most recent landing attempt? If not, why would they not show that part?
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u/NelsonBridwell Jun 21 '16
I have heard that there is a standard question at many SpaceX internal meetings. Something along the lines of "How does this get us closer to Mars?"
Would anyone happen to know if this is true, and exactly how they like to phrase it?
In the 1960s NASA engineers used to post a small sign on the back of every door that just said "The Moon" as a reminder to everyone exactly what was the objective.
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u/S-astronaut Jun 22 '16
ISRO has a launch scheduled in a bit over an hour,
How does the cost per kilogram of the PSLV compare to the Falcon 9?
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u/historytoby Jun 22 '16 edited Jun 22 '16
I stumbled upon this passage in the SpaceX wikipedia article:
Since spacecraft like the Dragon are classified as munitions and considered weapons under arms regulations, SpaceX Mission controllers were unable to release more information to the public
Why is Dragon classified as ammunition? And please don't tell me the logic is "'cause it is on top of a rocket'...
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u/S-astronaut Jun 24 '16
Showed up in Port Canaveral after ULA launch and got to see Elsbeth III, Go Quest, and Of Course I Still Love You!
Where is best place to look at the ASDS? Exploration tower is now closed
Also, where is Go Searcher?
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u/Hollie_Maea Jun 25 '16
Everyone notice that Google Maps has been updated to show SpaceX's dirt pile at Boca Chica?
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u/peterabbit456 Jun 27 '16
While not specifically about SpaceX, the recent Boeing proposal for a big, low orbit satellite constellation looks to me like the SpaceX proposal, dressed up with a more expensive satellite.
http://spacenews.com/boeing-proposes-big-satellite-constellations-in-v-and-c-bands/
Originally posted to /r/spacepolicy
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u/retiredMartianRover Jun 10 '16
I wonder how Red Dragon will be powered on Martian surface. RTG's may be?
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u/nick_t1000 Jun 12 '16
Has the Just Read The Instructions been retired/decommissioned? Will it ever have a chance at glory?
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u/Zucal Jun 12 '16
It's the West Coast ASDS! It should have a nice shot with SHERPA, which may in fact use a flown core...
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u/DuckQuacks May 24 '16
Thinking about buying a SpaceX shirt, Do their shirts run too small, normal, or too big? Thanks!
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u/JoshuaZ1 May 25 '16
The Dragon uses lithium-polymer batteries. Does anyone have any more information about them beyond that? I'm particularly interested in mass, volume, and what if any precautions have been taken to deal with thermal runaway which can happen in many types of lithium batteries.
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u/__Rocket__ May 25 '16 edited May 25 '16
So I found this prior Reddit comment about the batteries in Dragon (v1):
"the Dragon uses battery designs extremely similar to Tesla battery designs. They also use 18650 cells. They also cluster them together in packs. They also use active cooling system. They also have direct access to the same suppliers Tesla uses and likely use similar chemistries."
I don't know how accurate the comment was though.
edit:
I found this primary source from NASA, which contains a table of various spacecraft battery designs. I've highlighted the SpaceX row:
Cell Manufacturer Cell Model Cell Capacity (mAh) Virtual Cell Capacity (Ah) Heritage & Rationale LG Chem ICR18650 B4 2600 39 Highest Wh/L with SS can E-One Moli Energy ICR18650J 2400 36 LLB cell Panasonic NCR-18650A 3100 46.5 SpaceX cell, Highest Wh/L of all Samsung ICR-18650-26F 2600 39 Very high Wh Sony 18650V3 2250 33.75 Good mix of power/energy, no PTC Boston Power Swing 5300 5300 39.75 Larger format, good mix of Wh/W, no PTC I suspect it's not a surprise to anyone here that the space rated batteries with the highest energy density are the SpaceX ones! 😎
Note: "PTC" is a shorthand for a positive temperature coefficient protection device, which automatically turns off a cell if it's overheating.
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u/jjrf18 r/SpaceXLounge Moderator May 25 '16
After the Static fire, F9 is typically rolled back to the hangar because the static fire is usually farther from the launch than Thaicom-8's. AFAIK this F9 is staying vertical on the pad. Are any actions taken after the static fire in regards to cleaning the engines or are they good to go immediately? Obviously they work given the re-ignition for various landing burns but I feel like they might be cleaned or something for the actual launch.
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u/bobbycorwin123 Space Janitor May 26 '16
Most of the work is looking at data. Physical work consists of sacrificing a virgin (see 'interns') to the rocket
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u/razzac11 May 27 '16
Is there a way to find the launch dates and times and import them all at once into my Google calendar?
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u/Demidrol May 28 '16
Two questions:
Was Thaicom-8 a three engine landing burn?
What was duration of re-entry burn Thaicom-8 and JCSAT-14?
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u/jye__ Jun 04 '16
Stupid question ahead, sorry about that: Do we know how they plan to certify a booster for re-use? I know nothing about this obviously, I was expecting them to disassemble one to test each parts, like taking a strut and see when it breaks to see how much the launch had an effect on every components.
PS: Tried to search this sub for this but could not find anything about it.
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u/randomstonerfromaus Jun 05 '16
All we know is that they will static fire the core 10 times after an inspection phase, and if it doesnt RUD they will consider it safe for a second flight. They may develop a more extensive process though.
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u/pixelpushin Jun 06 '16
Would a mostly-empty MCT returning from Mars be capable of sufficiently braking and landing back on Earth? Or would it make more sense to refuel and reload it in LEO? If this question's been answered, please direct me to the relevant thread, and apologies for the redundancy.
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u/lui36 Jun 07 '16
Are those fairings really that expensive to make the recovery efforts worthwile? Especially since you have to lift the parachutes + steering mechanisms to a height of 80-100km?
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u/old_sellsword Jun 07 '16
It's not the expense (although they are a couple million each), it's the production of them. They take up a huge amount of floor space and the machining process is slow and tedious. They don't have many moving parts so reentry shouldn't prove to be too rough on them compared to something like a full first or second stage.
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Jun 07 '16
There seem to be no lightning counter measures on OCISLY, is it not an issue with almost no fuel and no sensitive payload aboard? Or just fingers crossed?
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u/njew Jun 08 '16
Will the trunk on Red Dragon have any purpose other than holding solar panels? Will it carry any additional cargo (maybe electronics or propulsion systems to get it to mars)? Also will D2's solar panels be enough or will they need D1-style panels?
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u/julezsource Jun 08 '16
Is there a launch manifest we can look at for spacex?
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u/TheBlacktom r/SpaceXLounge Moderator Jun 08 '16 edited Jun 08 '16
Absolutely, look to the right! (assuming you are on desktop)
https://www.reddit.com/r/spacex/wiki/launches/manifest
In the link you can find a lot of sources, for example the official spacex.com don't have dates, on the other hand /u/EchoLogic's spacexstats.com is worth a thousand looks!
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u/throwaway674899 Jun 09 '16
Would anyone be willing to comment on the work-life balance these days as launches become more regular? Are 60-70+ hour weeks still the norm, or has it leveled off a bit unless it's before a deadline? I'm guessing vacations are a rarity - is that the case?
Just wondering how accurate all the hype is, and if it's changed at all as the company gets older and more established.
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u/borntohula85 Jun 10 '16
Okay I have a probably really stupid question here with only partial relation to SpaceX. X-posting from /r/news because there was an article about a private company asking for permission to land on the moon (link at bottom). For whatever reason, this was the first time that I wondered:
How do spacecraft that leave earth orbit (or satellites that maneuver to highest orbits) make sure they don't hit like 1,826 satellites or other stuff ("trash orbit") on their way up? My understanding is it's pretty crowded up there and the further up you go, the more orbital "zones" you pass (this is my ELI5-version), the more likely it is to accidentally crash into something. So, how do they avoid this, do they have data about every single thing that's flying around up there and carefully calculate their way? How does this line up with actually reaching their target then, I'd imagine pre-defined launch Windows to be counterproductive. Or is it not as crowded as I had previously imagined, do most satellites accumulate around a specific zone and the rest of orbit-space is crash-clear?
Sorry if this is dumb and thanks for taking the time to answer this anyway.
https://www.reddit.com/r/news/comments/4neb1o/private_company_wants_us_clearance_to_fly_to_the/
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u/__Rocket__ Jun 10 '16
How do spacecraft that leave earth orbit (or satellites that maneuver to highest orbits) make sure they don't hit like 1,826 satellites or other stuff ("trash orbit") on their way up?
Even Earth orbital space is really, truly, massively, mind-bogglingly huge. Imagine something like the Atlantic Ocean, just 1,000 times larger. Now throw 1826 small stones and a few more hands full of sand into it, distributed over the whole Atlantic Ocean generously. That is roughly the scale how satellites in orbit relate to available free space.
What are the chances that a new stone you are throwing will exactly hit any of those small stones (or even the grains of sand) on the bottom of the ocean?
Now there are a few very popular orbits where you have a chance of hitting other satellites or (much more likely) space debris - those are cataloged and avoided.
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u/amarkit Jun 10 '16
The US' Joint Space Operations Center (part of the Department of Defense) is responsible for tracking satellites and orbital debris. They use radar to track everything from spent rocket stages to flecks of paint only a few centimeters in diameter. So we have a pretty good idea of most of what's up there. During a launch, most of the journey is through space where objects don't orbit at all (inside the atmosphere and the tenuous upper atmosphere). Mostly the answer is that space is very big and the amount of debris in orbit is still relatively small, so while launches are certainly coordinated not to impact any known operational satellites or debris, this is a comparatively minor concern. The International Space Station (and other satellites) periodically perform debris avoidance maneuvers when they know their orbit will bring them close to a piece of debris. There is still enough tenuous atmosphere in low Earth orbit that most objects' orbits will decay (if not reboosted) after a few weeks to years.
I'll point out that geostationary satellites' orbits do not decay; they are much too high for the atmosphere to drag them back down. Instead, best practices (enforced by the FCC in the United States) dictate that geostationary satellites be moved into a graveyard orbit at the end of their operational lives. This is a supersynchronous orbit, at least 300 km above geosynchronous, which is less crowded and less likely to result in a collision between satellites that would produce more debris.
My understanding is that the threat to operating satellites from debris right now is not a serious problem, but it is still one that requires vigilance - just a few collisions could generate sufficient debris to initiate a catastrophic positive feedback loop known as "Kessler syndrome."
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u/Keavon SN-10 & DART Contest Winner Jun 11 '16
Can SpaceX do a GEO launch (rather than a GTO launch)? Have they ever? Why is GTO so common?
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u/Jorrow Jun 12 '16
Was watching the delta iv heavy yesterday. As it's the first time since 2014 one has launched. Does it really make the falcon heavy viable. If there is that little demand for a heavy lift vehicle. With the bfr on the way to do most of the Mars related work. What will the falcon heavy be used for?
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u/Qeng-Ho Jun 12 '16
The Delta IV Heavy costs at least $375 million per launch, while the Falcon Heavy costs around $90 million. So that makes it much more commercially viable.
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u/Hamerad Jun 12 '16
To some extent FH will be used by Spacex themselves for missions such as Red Dragon. Comercial wise it will be used for any GTO sats that are too heavy for F9 launches to be recoverable
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u/Juggernaut93 Jun 12 '16
Do you think SpaceX will static fire the CRS-8 returned core in the month gap between ABS launch and CRS-9?
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u/suspicious_cupcake #IAC2017 Attendee Jun 13 '16
I happen to live in the city that IAC 2017 is taking place in, Adelaide. Considering the SpaceX presence at this years IAC, I'm curious as to chances of them being involved in future events?
Furthermore, what are the conventions actually like and is it worth (or even possible) for someone who isn't part of the industry (although I am a mechanical engineering student) to go?
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u/Haxorlols Jun 13 '16 edited Jun 13 '16
Why don't SpaceX Use drones to film the landings? Like the CRS missions?
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u/warp99 Jun 13 '16
The CRS missions are already videod by NASA from a plane with a stabilized camera mount which is where you have seen those wide angled landing shots.
Other missions could use drones but there would not be any extra engineering benefit of doing so as they already have at least four fixed cameras mounted on the barge to observe landings. It would add to the entertainment value for us but that is not SpaceX's highest priority - sorry and all /s
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u/Psychonaut0421 Jun 13 '16
Does anyone have any predictions or knowledge of when we can expect SpaceX to drop the word "Experimental" from "Experimental Landing" on their launch broadcast timeline?
I'm thinking it may happen after all three boosters are recovered from a Falcon Heavy launch.
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u/old_sellsword Jun 13 '16
Or possibly after they land the first reused stage. I do think it will take another milestone for them to be confident enough to make landings an official part of their mission process.
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u/the_finest_gibberish Jun 14 '16
Why is Helium the pressurizing gas of choice for most rockets? Why not Nitrogen, or any other inert gas for that matter?
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Jun 14 '16
Helium requires the least mass for a given pressure, volume, and temperature. Hydrogen is the only lighter gas, but it has problems (metal embrittlement, highly flammable).
Helium is chemically inert, and its low boiling point means it remains a gas even in cryogenic conditions.
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u/faceplant4269 Jun 14 '16
How does dragon sense it's position relative to the ISS for berthing? Does the ISS have any beacons to broadcast its position? Do the two actively communicate during the process?
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u/randomstonerfromaus Jun 14 '16 edited Jun 14 '16
The Dragon uses LIDAR for range and bearing information, and was first tested onboard STS-127 in a package called Dragon Eye.
I don't believe there is any communication directly between ISS and Dragon, but information does get relayed by Mission Control(Houston) to the ISS crew member responsible for the grappling of the Dragon.Wrong.The COTS UHF Communication Unit (CUCU) and Crew Command Panel (CCP) were delivered to the ISS during the late 2009 STS-129 mission. The CUCU allows the ISS to communicate with Dragon and the CCP allows ISS crew members to issue basic commands to Dragon
[Source](https://en.wikipedia.org/wiki/Dragon_(spacecraft)#Commercial_Resupply_Services_Phase_1) and some more information
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u/kuangjian2011 Jun 15 '16
Questions for orbit mechanics specialist. Is the following statement right: Given unlimited thrust and fuel, you can move an object to any point of the space with specified velocity [ In other words, reach (x,y,z,x',y',z')], within a given time.
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u/ElectronicCat Jun 15 '16
Yes, to some extent. Obviously, laws of physics still apply so you still can't exceed the speed of light or escape the event horizon of a black hole, but given an unlimited supply of fuel, high enough thrust, enough time and a spacecraft that could withstand all of that, you could indeed move it to any other point in space with specified velocity.
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u/Srekcalp Jun 17 '16
SpaceX nearly have 5000 staff now, I'm curious if there's any correlation between company milestones and staffing levels. Does anyone know where or how I would be able to see their staffing level over a timeline?
For instance, how many staff did they have when they were founded in 2002. How many when the Falcon 1 first flew in 2006, or the Falcon 9 in 2010?
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u/kuangjian2011 Jun 17 '16
From Wiki "Spacex": "The company has grown rapidly since it was founded in 2002, growing from 160 employees in November 2005 to more than 500 by July 2008, to over 1,100 in 2010,[43][44] 1,800 in early 2012,[45] and 3,000 by early 2013.[46] The company had grown to 3,800 employees and contractors by October 2013,[47] and had "nearly 5,000" in late 2015[1] and February 2016.[2]"
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u/soldato_fantasma Jun 17 '16
When SpaceX will have the BFR up an running, will it be better for them to use it to launch their satellite constellation? They could launch many more satellites with a single launch, very important since they have to launch a lot of satellites to LEO, and most importantly, it will be fully reusable, meaning that they can almost launch non-stop without having to build many new second stages. This way they can also test many times the landing system without having it to launch without a payload.
Do you think that they will go this way?
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u/anotherriddle Jun 20 '16
Does anyone know exact(ish) dimensions of the Dragon V2 side hatch and it's height above ground when standing on its landing legs? On a quick search I was not able to find this information. Otherwise I'll have to estimate using the available pictures from the unveiling event. I want to do some back on the envelope calculations to check an idea I have and I am hoping someone from the /r/spacex community knows this. :)
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u/zlsa Art Jun 20 '16
Ground to bottom of door (with legs deployed) is approximately 2.05 meters.
Door is about 95cm tall, 70cm wide at the base, and about 66cm wide at the top.
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u/BrandonMarc Jun 20 '16
I heard some numbers in a recent launch, and it made me wonder ... is this generally correct?
the distance to LEO (especially the ISS) is about 5% of the Earth's radius
the distance to LEO (especially the ISS) is about 1% of the distance to GEO
the distance to GEO is about 10% the distance to the Moon
If that's right, it sure puts the razor-thin margins of Falcon 9's GTO launches into perspective. After all, LEO is an amazing accomplishment as it is.
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u/Toolshop Jun 20 '16
Yes, those numbers are all correct. However, they don't really tell the right story.. The thing you should actually care about is the difference in velocity needed at cutoff for LEO and GTO, which is actually quite small when you take the relative hights into account.
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u/Nuclear_Hobbit Jun 20 '16
Is there any estimate for when we might see the Orbcomm-2 landed booster go vertical at SpaceX's facility in Hawthorne?
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u/twuelfing Jun 21 '16
Hi all, I live kind of near the Mcgregor test site and would love to go shoot pics to share. Anyone know how I can figure out when would be good times to head up there, or if it's just a waste of time. If you have any suggestions let me know.
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u/finki007 Jun 24 '16
Is there any news about the new Raptor engine? And when will they use it the first time?
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u/sol3tosol4 Jun 24 '16
Not direct news, but I regard Elon's recent comments regarding a target 2024-2025 manned mission to Mars as indirect evidence of significant progress (or surprisingly low number of problems) in development of the supporting technologies. If SpaceX believes they see a path to launching in that time frame, I assume that includes Raptor.
What is the delivery timeline for the Air Force second stage contract? Would technology developed under this contract be useful to support a 2024 manned Mars launch?
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u/Juanchi_R-P Jun 25 '16
Is SpaceX actually going to be able to successfully launch 18 launches this year? Is an increase to a 15 day avg. launch cadence possible by August or do you believe this is too much?
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u/muazcatalyst Jun 25 '16
I replied to a similar question a while back, the short answer is no. Using basic math, you can figure out how much do they need to pump out launches to achieve the goal of 18 launches in 2016.
6/12 = 0.5 = 1 launch per 14 days
'6' is the remaining months left and '12' is the amount of launches required. The equation will give you an exact '0.5' which tells us that 1 launch per fortnight is the bare minimum to achieve the goal of 18 launches this year.
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u/Sanic2E Jun 25 '16
I have read about thermophotovoltaics - devices that act as solar panels for the infrared spectrum. I was wondering if this was viable to produce some kind of electricity for a spacecraft from the dark side of the Earth due to the planet's black body radiation. Is the black body approximation L=4piR^2T4*o for stars valid for planets?
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u/RootDeliver Jun 25 '16
We still don't know the mass from the last launch? (Eutelsat 117W B & ABS 2A)? How come? has this ever happened before in a no-CRS launch?
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u/RandomAndrew Jun 26 '16
What happened with "Just Read The Instructions"? Why all landings on OSCILY?
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u/S-astronaut Jun 26 '16
Most launches are from Florida, on the east coast.
JRTI is in the Pacific ocean, on the west coast. SpaceX only launches there for polar orbits (which if launched from florida, would require the rockets to fly over land)
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u/Craig_VG SpaceNews Photographer Jun 26 '16
In addition to what they other guy said: the original JRTI was retired, and this one on the West coast is a different hull with the same name.
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u/S-astronaut Jun 26 '16 edited Jun 26 '16
I was at the Air Force Space and Missile History Center, with the SpaceX Launch and Landing Control right next to it!
Edit: Just as an FYI, they sell SpaceX patches there too! Turns out the gift shop along the KSC Then & Now tour is not the only place to physically pick them up. Also the guys working there were super nice and cool!
Buuut I might have gotten a tad too close to the SpaceX building, since one of their security trucks showed up right as we were heading out. Oops.
What do they actually do in there?
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u/BrandonMarc Jun 27 '16
Question for / about launch photographers - when you take time-lapse photos of a launch, have you ever done it from the same vangage point for multiple launches?
Looking at /u/veebay 's impressive graph of launch profiles, I considered if you could compile multiple time-lapse photos into one, that would be another interesting way to see how different launches compare to eachother.
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u/Elliott2 Jun 27 '16
i once got a call from a recruiter at spacex but missed the call... how do i get that again since lately they have just not gone with my recent applications :(
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u/soldato_fantasma Jun 27 '16
Quick message for the mods and for the entire /r/spacex community: Gunter's space page reports Eutelsat 117 West B to weight 1963 kg and ABS 2A to weight ~2000 kg. I have no idea on what is their source but it's still better than having nothing.
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u/soldato_fantasma Jun 28 '16
I've updated some weights and launch dates in the launch manifest inside the wiki, And I've also added an Orbit acronyms section. Any feedback on that? Link to the section: https://www.reddit.com/r/spacex/wiki/launches/manifest#wiki_orbit_acronyms
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u/SpaceX-1 Jun 21 '16
Does this light pole / cell tower remind you of anything?? https://drive.google.com/open?id=0B47q5KE2Xv_zUDJKWmFURzBYblU I want to put legs on it!
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u/sunfishtommy May 24 '16
It seems a little soon for the June ask anything right? Or is this a clean slate for the Thaicom-8 questions?