SpaceX COTS-2/3 Flight

[NEOWatcher]

Chase plane footage that was recorded onboard has been released: http://www.nasa.gov/multimedia/video...a_id=145209661 or on Youtube

Cool, thanks.

The 2 minutes that the chutes were open seemed very long to me. Now, that's only an impression from an over 40 year old memory of watching live Apollo splashdowns. So; I could be completely wrong. Time went by so fast in those days.

But; that impression did make me think of how Dragon and Apollo splashowns compare. I tried doing some searches to get a perspective, but can't nail it down. So; can anyone answer the following for both Apollo and Dragon?
- Altitude at parachute deployment.
- Speed at parachute deployment.
- Amount of time between that and splashdown.

[Swift]

But; that impression did make me think of how Dragon and Apollo splashowns compare. I tried doing some searches to get a perspective, but can't nail it down. So; can anyone answer the following for both Apollo and Dragon?
- Altitude at parachute deployment.
- Speed at parachute deployment.
- Amount of time between that and splashdown.

If there are differences, I wonder how much of that is because of the different technology, or because of manned versus unmanned. I suspect that cargo is allowed to take a harder hit upon splashdown than people. And if there is a difference between manned and unmanned, will SpaceX change th splashdown for the manned version?

[ugordan]

I suspect that cargo is allowed to take a harder hit upon splashdown than people.

I don't know the actual numbers offhand, they can be found by a google search, but Dragon splashdown is supposed to be more gentle than Apollo, not less.

[NEOWatcher]

If there are differences, I wonder how much of that is because of the different technology, or because of manned versus unmanned. I suspect that cargo is allowed to take a harder hit upon splashdown than people. And if there is a difference between manned and unmanned, will SpaceX change th splashdown for the manned version?

Glad you mentioned that, because that thought ran through my head too. Especially after seeing a page about the 3rd apollo parachute being a backup (which went into practice) and one about how the capsules possibly being upside down in the water.

I just don't know how to express a question relating to the terminal velocities of with and without chutes.

[NEOWatcher]

I don't know the actual numbers offhand, they can be found by a google search, but Dragon splashdown is supposed to be more gentle than Apollo, not less.

Now that you mention it, isn't the Dragon profile already designed with humans in mind?

[ugordan]

Yes, and just like with Apollo the 3rd parachute is more of a backup than necessity.

[djellison]

Elon said in a press conf that the entry and landing profile for manned would be the same as for cargo.

looking at
http://www.spacex.com/downloads/COTS...it-5-14-12.pdf
and
http://ntrs.nasa.gov/archive/nasa/ca...1973062665.pdf
http://www.apollosaturn.com/as202/p14-18.htm


Drogue deploy
SpaceX 40kft
Apollo 23kft

Main Chute Deploy
SpaceX 10kft
Apollo 10kft

Splashdown speed
Apollo 28fps
SpaceX 16-18 fps

[kamaz]

Apollo would enter atmosphere travelling at 11km/s, Dragon reenters at less than 8km/s.

[ugordan]

What's your point? What bearing does that have to parachute events and splashdown speed?

[djellison]

What's your point? What bearing does that have to parachute events and splashdown speed?

Quite - it has no impact at all. Not sure what Kamaz's point is. These values are the same for Apollo 7 thru Apollo 17. And indeed, they'd be the same for a Dragon returning from BEO ( which it could without modification )

[Trebuchet]

Apollo would enter atmosphere travelling at 11km/s, Dragon reenters at less than 8km/s.

I suspect you mean m/s, not km/s!

[Grashtel]

I suspect you mean m/s, not km/s!

Kamaz is talking about atmospheric entry speeds which means that km/s is the correct unit.

[Trebuchet]

Kamaz is talking about atmospheric entry speeds which means that km/s is the correct unit.

Oh, I see now. That's better!

[Polyrealastic Observer]

Does anybody have a guess as to what that diagonal seam is on the exterior of the Dragon? I've looked at some fact sheets, and it's not mentioned.

[Van Rijn]

I was guessing it had to do with the parachutes and line deployment, and that's what I'm seeing elsewhere (google 'dragon seam parachute spacex OR capsule'). You can see the lines here in space:

http://i.space.com/images/i/17911/or...jpg?1338324890

and here's the Dragon capsule from an earlier flight, post landing:

http://www.universetoday.com/wp-cont...51-580x385.jpg

[djellison]

It's exactly that. The chutes are packed in the service space of the capsule near the bottom. Those lines carry the risers from the chutes to where they actually bolt to the top of the capsule. They rip open when the chutes are deployed.

[ugordan]

A few more recovery photos have been added to the SpaceX gallery:

http://spacexlaunch.zenfolio.com/p208064181/h37af01f1
http://spacexlaunch.zenfolio.com/p208064181/h3fc513ed
http://spacexlaunch.zenfolio.com/p208064181/h2ad9853d
http://spacexlaunch.zenfolio.com/p208064181/h3dbaea42

[Polyrealastic Observer]

It's exactly that. The chutes are packed in the service space of the capsule near the bottom. Those lines carry the risers from the chutes to where they actually bolt to the top of the capsule. They rip open when the chutes are deployed.

Ah! I see the mortars now. What a good solution, considering there's really no room around the docking interface. Thanks dj and Van. Now, has anybody seen a link to what needs to be done to turnaround the craft for another flight? Obviously the PICA shield will need replacement, but I'm wondering about other things like, do they expect the thrusters will need to be replaced, or just tested. It's so neat learning the nuts and bolts of a new vehicle. I'm very impressed with how 'mature' this craft seems after only 2 flights.

[Trebuchet]

It's exactly that. The chutes are packed in the service space of the capsule near the bottom. Those lines carry the risers from the chutes to where they actually bolt to the top of the capsule. They rip open when the chutes are deployed.

You can see where the chute lines channels are on the exterior of the spacecraft in several of the on-orbit photos as well. I'm recalling that for the Apollo spacecraft, the astronauts actually had to remove the chutes from the nose of the capsule for access to the docking hatch and put them back in place for reentry. Is that correct?

[Polyrealastic Observer]

You can see where the chute lines channels are on the exterior of the spacecraft in several of the on-orbit photos as well. I'm recalling that for the Apollo spacecraft, the astronauts actually had to remove the chutes from the nose of the capsule for access to the docking hatch and put them back in place for reentry. Is that correct?

I wouldn't think so. Those parachute canisters arranged around the exterior of the docking tunnel, not inside it. As far as I know.

[cjameshuff]

Ah! I see the mortars now. What a good solution, considering there's really no room around the docking interface. Thanks dj and Van. Now, has anybody seen a link to what needs to be done to turnaround the craft for another flight? Obviously the PICA shield will need replacement, but I'm wondering about other things like, do they expect the thrusters will need to be replaced, or just tested. It's so neat learning the nuts and bolts of a new vehicle. I'm very impressed with how 'mature' this craft seems after only 2 flights.

The heat shield is intended for multiple uses, at least when used for LEO reentries. Musk has stated that it could potentially be used hundreds of times. I don't know if this involves refurbishment (like re-impregnation with phenolic resin or something) or not.

[kamaz]

http://www.universetoday.com/wp-cont...51-580x385.jpg

Looks as if it has landed in someone's backyard...

[NEOWatcher]

Quite - it has no impact at all. Not sure what Kamaz's point is. These values are the same for Apollo 7 thru Apollo 17. And indeed, they'd be the same for a Dragon returning from BEO ( which it could without modification )

Apollo would enter atmosphere travelling at 11km/s, Dragon reenters at less than 8km/s.

Minor nit: Apollo 7 was less than 8km/s.
But; both being designed for BEO and humans, and from what I see of the re-entry, I do see a lot of equivalencies between the two even if they are different.
Thanks everyone.

[djellison]

Minor nit: Apollo 7 was less than 8km/s.

I was citing parachute opening altitudes, which WERE the same for all Apollo missions.

That 7 (and 9) were from LEO is irrelevant. (as indeed were 4, 6 and a couple of other test flights for CSM testing)

[NEOWatcher]

I was citing parachute opening altitudes, which WERE the same for all Apollo missions.

Sorry; I got your comment mixed up with the re-entry comments in context with what you replied to. On hindsight, I do see parachute speed is in context too.
If I got it mixed up, maybe someone else would have too. (he says as he tries to redeem himself )

[DoggerDan]

I just read Space X and Bigelow Aerospace (makes of inflatable habitats) are teaming up.

Probably old news to most of you. I'm curious as to their overall cost structure. I'm wondering if Bigelow figured out how to build space stations significantly cheaper than the ISS, and whether SpaceX's $/lb to LEO is in the same ballpark as other one-shot spacelift systems, or whether it's significantly less.

If cheaper on both accounts, then perhaps this isn't a fluke and we really are entering the new era of the privatization of space exploration!

[Nicolas]

I'm wondering if Bigelow figured out how to build space stations significantly cheaper than the ISS

If you look at the m³ aspect only, the inflatable part is your answer.

[Garrison]

I just read Space X and Bigelow Aerospace (makes of inflatable habitats) are teaming up.

Probably old news to most of you. I'm curious as to their overall cost structure. I'm wondering if Bigelow figured out how to build space stations significantly cheaper than the ISS, and whether SpaceX's $/lb to LEO is in the same ballpark as other one-shot spacelift systems, or whether it's significantly less.

If cheaper on both accounts, then perhaps this isn't a fluke and we really are entering the new era of the privatization of space exploration!

In the interests of fairness NASA did the original research on inflatables, then funding was cut and they sold the R&D on to Bigelow.

[mutleyeng]

bigalow also needs the falcon heavy though dosnt it?
I dont think the inflatabe part fully explains the cost discrepancy. Im a bit skepital, but i really do want my skepticism to be shown to be unfounded. It really would be a game changer.

[NEOWatcher]

I dont think the inflatabe part fully explains the cost discrepancy.

I agree with that. I think a lot has to do with the equipment that it contains. ISS (and Skylab/Mir) were equiped with extensive experiments and long term habitation in mind.

I think of Bigelow's base price as a bare minimum equipment price. It's going to start to get more expensive as you add the leather wrapped steering and heated seats.

Im a bit skepital, but i really do want my skepticism to be shown to be unfounded. It really would be a game changer.

I'm not skeptical.
Although having a private source for a habitation module is definitely a game changer, I just don't think it's as big as some people think.