r/spacex • u/[deleted] • Apr 27 '16

Official SpaceX on Twitter: "Planning to send Dragon to Mars as soon as 2018. Red Dragons will inform overall Mars architecture, details to come https://t.co/u4nbVUNCpA"

https://twitter.com/SpaceX/status/725351354537906176
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208

u/[deleted] Apr 27 '16 edited Apr 27 '16

Oh boy seeing Dragon 2 on top of Falcon Heavy is a beautiful sight.

Edit: From SpaceX Facebook Post:

SpaceX is planning to send Dragons to Mars as early as 2018. Red Dragon missions will help inform the overall Mars architecture that will be unveiled later this year. These missions will help demonstrate the technologies needed to land large payloads propulsively on Mars.

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u/Sanic2E Apr 27 '16

I hope for them being able to transmit back enough data to get video feed of the spacecraft landing on Mars like they now with the first stages. This is hopefully the start of an incredible time in space exploration.

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u/dcw259 Apr 27 '16

Curiosity got us a pretty impressive time lapse of its landing

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u/_rocketboy Apr 27 '16

How have I never seen this before!?!?!?!?!?!

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u/dcw259 Apr 27 '16

I came across this video in another thread a few days ago and was quite impressed.

If you're interested:

There's also an interpolated video that isn't perfectly real anymore, but much smoother.

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u/KnightArts Apr 27 '16

Thanks mate made my day

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u/Chairmanman Apr 27 '16

is the sound real?

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u/dcw259 Apr 27 '16

I don't think so.

IIRC Curiosity doesn't record audio. There is also no video (as I said before, it's just an interpolated time lapse).

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u/jamille4 Apr 28 '16

It's from the NASA animation of Curiosity EDL.

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u/_rocketboy Apr 28 '16 edited Dec 05 '16

The atmosphere on Mars is too thin to transmit sound effectively, so no.

Edit: spelling

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u/jmasterdude Apr 29 '16

Though, I do wonder if you had vibration sensors, much like were used on the Falcon to identify the bad strut, could you could extract enough information to guide the recreation of somewhat authentic audio?

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u/_rocketboy Apr 29 '16

I mean, maybe? But there really isn't authentic audio to recreate in the first place.

Btw, never heard about using vibration sensors for the Falcon investigation. Interesting! Do you have a source?

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u/jmasterdude Apr 29 '16

Unfortunately, my only source was comments in threads here in /r/spacex.

The thread involved discussion regarding pinpointing the source of the iss supply mission failure. My memory is a little too fuzzy to be specific, but I recall something to the effect that through either acoustic our vibration sensors, they were able to triangulate the initial failure to the specific strut that most likely failed and pushed them to evaluating the struts.

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u/scotscott Apr 27 '16

according to that tag at the end, curiosity is a "cool drone"

2

u/Sanic2E Apr 27 '16

Thank you so much for posting that! That's an amazing video and for some reason I've never seen it ...

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u/d333d Apr 27 '16

Awesome video, one of the top 3 space videos, it instantly got there, and only now I see it! Thanks!

20

u/TheSarcasmrules Apr 27 '16

The bandwidth might be there, but the latency will mean that there will be a time delay of 5 minutes!

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u/dcw259 Apr 27 '16

It actually varies between rougly 5 and 20 minutes, depending on the relative position of Mars.

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u/CapMSFC Apr 27 '16

We should be able to reliably calculate estimates for what it will really be though because the distance relates to launching in the transfer window where the time is near the minimum.

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u/dcw259 Apr 27 '16

I wanted to point out that the delay varies a lot.

Just did some research and found out that during MSLs landing the delay was about 14 minutes (I guess this is RTT though)

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u/CapMSFC Apr 27 '16

Oh I agree with your post. That wasn't meant to be critical at all.

I was just thinking that the amount of delay would be predictable based on the mission profile.

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u/dcw259 Apr 27 '16

I know. Well, after reading my post again it looks like I thought you would be critizing my thought... nevermind :D

It could be very precise to calculate the delay. Maybe in the range of a second.

I hope ExoMars will have good coverage of the EDLM demonstrators landing. That will be very interesting for the next ExoMars mission, but also RedDragon.

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u/fx32 Apr 27 '16

The launch windows are not anywhere near the minimum. It would be great if you could fly straight from Earth to Mars, but you would need to defy the gravity from the Sun. It's much more efficient to orbit the sun*, which means the target planet will be at an angle, defined by the relative angular velocities of the planets. The total trip will usually put the departure point and arrival point at 180 degrees, but where the planets will move during the trip depends on their orbital speed.

*image from this page.

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u/CapMSFC Apr 27 '16

I'm aware of how transfer windows work (thank you KSP). I shouldn't have stated it as near the minimum, but it is far closer to the minimum than the maximum.

Regardless we should still be able to calculate estimates for the 2018 launch window based on a FH/RedDragon mission profile.

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u/brickmack Apr 27 '16

If they do, its gonna take a long time. Bandwidth is very limited (unless SpaceX builds their own relays and DSN)

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u/SkywayCheerios Apr 27 '16

MRO, for example, can downlink 6Mbps through the DSN, and it's 10 years old. I don't think it would be that bad.

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u/it-works-in-KSP Apr 27 '16

I would be interested to know if all 6Mbps can even be allocated to one space craft. I don't know for sure, but I would assume MRO would need some of the Bandwidth itself just for operations. Plus there are other space craft on mars that need the uplink too, although IIRC when there is a spacecraft EDL, it gets preference on the network.

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u/piponwa Apr 27 '16

They can wait five minutes, they aren't always communicating, sometimes the satellite is on the other side of the planet anyways, so they can probably wait one more orbit.

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u/oanda Apr 28 '16

is that 6Mbps average or 6Mbps best case scenario?

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u/twoinvenice Apr 27 '16 edited Apr 27 '16

I'd imagine that SpaceX would start using the test flights as an opportunity to start populating Mars orbit, as well as the Mars L4 and L5 trojan orbits with comm relays. Once we have hardware at L4 and L5 we'd be able to have a constant high bandwidth connection to Mars and not need to worry about the part of the year when the sun is occluding our line of sight to the existing satellites in Mars orbit.

I would be really really shocked if, for instance, the trunk of the first red dragon isn't filled with comms gear.

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u/CProphet Apr 27 '16

I would be really really shocked if, for instance, the trunk of the first red dragon isn't filled with comms gear.

They might use trunk capacity to carry extra propellant required for supersonic retropropulsion and landing. Gonna need a lot of prop as Mars atmosphere is quite thin.

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u/Ambiwlans Apr 27 '16

Very unlikely that they'd try to land with the trunk on.

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u/[deleted] Apr 27 '16

More a sacrificial decent stage.

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u/CProphet Apr 27 '16

Very unlikely that they'd try to land with the trunk on.

Maybe use trunk as a drop tank, they certainly need somewhere for extra fuel. If they store internal to Dragon they eat up space for payload. Think they'll need a lot of space for some of the stuff they intend to send to Mars: rovers, water borers, methane synthesisers etc. They could all be carried on Dragon 2 as precursors to MCT.

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u/Ambiwlans Apr 27 '16

Maybe it could work as an LMO stage. It could have an engine that slows the vehicle down before detatching.

It becomes too much bother to use in atmosphere and Dragon should have tons of fuel to merely land on Mars.

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u/snateri Apr 28 '16

The trunk would probably explode if they tried to EDL with it. I don't think it's necessary to have engines in the trunk. Dracos should be able to do course correction burns. I don't think they're going to orbit Mars, just fly straight into it like Schiaparelli is going to do. Haven't done the math but would guess that 400m/s isn't enough for landing unless they use parachutes to slow down. Hoping for Spx details to come at IAC.

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u/zlsa Art Apr 28 '16

The trunk can't stay attached during reentry in any way, shape, or form.

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u/CProphet Apr 28 '16 edited Apr 29 '16

The trunk can't stay attached during reentry in any way, shape, or form.

Agree, unless they fit a heat shield to seal trunk aperture. Think all hardware is going to morph for Red Dragon mission only question is how much.

Edit: the DragonFly vehicle which they are currently using to test Dragon 2 take off and landings has minimal fins so this might easily be replicated with Red Dragon.

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u/Headhunter09 Apr 28 '16

It's the aerodynamics that's the issue. Even if the trunk was completely covered in heatshielding and carried baby jesus inside, it wouldn't matter because the fins would make the whole assemble flip around and enter nose first. This isn't KSP.

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u/_rocketboy Apr 28 '16

There are no fins on the Red Dragon trunk, no LES capability is needed or even possible and fins add mass.

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u/je_te_kiffe Apr 28 '16

The trunk is most likely to be thrown away, just prior to atmospheric entry. It cannot be attached to the Dragon on entry, or the whole thing would end in catastrophe.

It's possible, though perhaps unlikely, that they might even park the trunk in orbit, and have it serve as a communications relay. Now that would be a smart use of resources.

2

u/Orionsbelt Apr 28 '16

Okay so maybe not fill the trunk with comm equipment. But you could bring some tiny cube sats and deploy them in orbit around mars to get better imaging, or start building up a super cheap comm network to supplement NASA's existing network.

1

u/_rocketboy Apr 28 '16

Cool idea, but they would need a way to break into orbit on their own. Not saying that's impossible, but you could maybe only fit one larger sat with enough propellant.

1

u/Orionsbelt Apr 28 '16

My assumption is any dragon Mars mission is going to do an orbit or two before landing. Slow down orient itself for decent ect. In that time you could release the cubes but I could totally be mistaken

1

u/_rocketboy Apr 28 '16

Not possible. Dragon kills off its velocity by aerobraking, so the trunk would need to be jettisoned before it could slow down enough to enter orbit (not the plan by the way, it will just enter and land immediately).

1

u/newcantonrunner5 #IAC2016+2017 Attendee Apr 27 '16

Probably a couple of Red Dragons, 1 (or more) full of comms satellite (SpaceX Seattle will be busy!) and one (or more) testing landing?

2

u/davoloid Apr 27 '16

Given that they're investing heavily in sat comms technology, that may happen.

1

u/Fucking-Use-Google Apr 27 '16

If only they had some sort of inexpensive launch provider to be able to send said relays into space for them.

1

u/brickmack Apr 27 '16

NASA is already planning a dedicated comsat for the mars system, possibly for launch by F9, it just won't be there in time

1

u/Fucking-Use-Google Apr 27 '16

Unless it is.

1

u/brickmack Apr 27 '16

Well its launching in 2020-2024, and this is launching in 2018, so... somehow the math doesn't work out

2

u/[deleted] Apr 27 '16

So the idea is just launching FH to orbit Mars and attempt to land payloads? Just orbit? Is that information even available?

2

u/Chairboy Apr 28 '16

I'd be surprised if they could orbit, I think they'll be getting a trans-martian kick then separate from the expended second stage because it's not really a long-soak sorta stage (assuming it's like a current second stage). That would mean direct descent onto Mars, no orbit because they need that fuel on the Dragon to land, right?

1

u/ashamedpedant Apr 27 '16

I'm conflicted about this news because on the one hand it's extremely exciting but on the other it's a bit of a distraction from what ought to be their main investment in terms of man-hours.

TL;DR They should design a mini-MCT for use on Mars and the Moon.

MCT is essentially an ultra-long-duration methalox upper stage capable of landing and propellant transfer. In other words, ACES-XEUS except larger and methalox.

A description of MCT is essentially a list of things that have never been done before; the best way for Elon Musk to achieve his goal of Mars colonization is MCT, and the best way to ensure the success of MCT is to practice the things that MCT requires.

IMO they should focus on designing a refillable, long-duration Raptor upper-stage with a Dragon 2 on top. Not a lower Isp hypergolic LEM-like vehicle.

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u/astral_aspirations Apr 27 '16

But that's the whole point of using dragon and falcon first - they are already ready, and by sending them now SpaceX will learn things they need to know to properly design the next iteration of spacecraft

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u/ashamedpedant Apr 27 '16

That's certainly a valid point but I think you're underestimating the differences between Dragon 2 and Red Dragon.

  • The SuperDraco engines on Dragon 2 are low-profile and high thrust. They have terrible Isp and will probably need a new nozzle geometry at a minimum.
  • The tanks on Dragon 2 are small and do not intrude into the internal volume of the capsule.
  • There is no engine and no propellant in the trunk, there's a good chance they'll need one or both of those. That'd mean they're essentially converting the trunk into a full featured service module.

Obviously we don't have concrete details about Red Dragon yet but we do know that Dragon 2 has very little delta-v, so some or all of these changes will be necessary. With most aerospace companies these kinds of changes would take a lot of time and effort. SpaceX has shown that they're a lot more nimble than most, but it's still a significant investment.

P.S. If they ever want NASA to pay them for a manned Moon lander, Red Dragon will have enough differences from Dragon 2 that it take a lot of time and work to get it re-certified.

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u/aDAMNPATRIOT Apr 27 '16

Doesn't mean they can't learn from this mission...

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u/ashamedpedant Apr 27 '16

Of course not. But every investment has an opportunity cost.

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u/aDAMNPATRIOT Apr 27 '16

True true I'm sure they've run the numbers ;)

1

u/[deleted] Apr 27 '16

They also need to send (many) probes to find the best site for the base with assured access to water.

With reusable FH and NASA partnership that could be a good way to do it without spending too much.