SpaceX COTS Demo 1 Updates

[Robotbeat]

I assume the Dragon capsule is designed to survive a ballistic (and passive) reentry, right?

So, if control is lost on the Dragon capsule, its orbit would decay and it'd survive reentry (although not landing!) if all power is somehow lost after it reached orbit and had shed its service module?

[beancounter]

I assume the Dragon capsule is designed to survive a ballistic (and passive) reentry, right?

So, if control is lost on the Dragon capsule, its orbit would decay and it'd survive reentry (although not landing!) if all power is somehow lost after it reached orbit and had shed its service module?

Well parts of it would survive landing - lol.

[e of pi]

I assume the Dragon capsule is designed to survive a ballistic (and passive) reentry, right?

So, if control is lost on the Dragon capsule, its orbit would decay and it'd survive reentry (although not landing!) if all power is somehow lost after it reached orbit and had shed its service module?

I may be wrong, but orientation is a big issue there. If oriented properly before power loss? I think it could survive entry, you'd just essentially be replacing the impulse of a retro burn with the cumulative drag effects. However, I'm not so sure it could survive intact it not oriented properly.

Parachutes might also be an issue. The capsule might survive entry only to plow into the ocean going far faster than designed.

[Comga]

I assume the Dragon capsule is designed to survive a ballistic (and passive) reentry, right?

So, if control is lost on the Dragon capsule, its orbit would decay and it'd survive reentry (although not landing!) if all power is somehow lost after it reached orbit and had shed its service module?

I may be wrong, but orientation is a big issue there. If oriented properly before power loss? I think it could survive entry, you'd just essentially be replacing the impulse of a retro burn with the cumulative drag effects. However, I'm not so sure it could survive intact it not oriented properly.

Parachutes might also be an issue. The capsule might survive entry only to plow into the ocean going far faster than designed.

Remember the Soyuz missions where the Service Module failed to detach as planned?  As soon as the reentry forces tore it away the capsules righted themselves.  Given sufficient stability, (including sheding the Trunk) a stable capsule will enter heatshield first.  And when it does that, one would suppose that its subsonic velocity at a few miles altitude would be close to nominal regardless of how it reentered.  Of course, if it lost power, it might not deploy the parachutes.

[docmordrid]

Using a terminal velocity calculator, SpaceX numbers for Dragon and a few guesses I got a terminal velocity for it  of 323.386 kph/200.943 mph.  Even if off by 25% that's NOT a soft landing.

[savuporo]

300kph is borderline doable for jumping out of an airplane. Not nice, but tolerable.

Can Dragon's hatch be blown for emergency skydiving ops ?

[Robotbeat]

Using a terminal velocity calculator, SpaceX numbers for Dragon and a few guesses I got a terminal velocity for it  of 323.386 kph/200.943 mph.  Even if off by 25% that's NOT a soft landing.

200mph sounds about right. I wonder if a single astronaut could bail out at that speed, within half a minute? It should be technically possible (though not at all safe), and smallish reserve parachutes are rather lightweight (a couple 8 kg).

EDIT:Thanks, savuporo.

[savuporo]

200mph sounds about right. I wonder if a single astronaut could bail out at that speed, within half a minute? It should be technically possible (though not at all safe), and smallish reserve parachutes are rather lightweight (a couple kg).

I just went and weighed mine : it 8 kilograms rig, 150sqft main canopy.

[docmordrid]

Have to free-fall a bit to slow to a normal human TV though since most 'chutes I've seen spec at ~140kts = 160mph/260kph.

[Robotbeat]

Have to free-fall a bit to slow to a normal human TV though since most 'chutes I've seen spec at ~140kts = 160mph/260kph.

I'm sure you'd have no problem getting a parachute opening spec at something like 350kph if you had to.

[Hauerg]

Have to free-fall a bit to slow to a normal human TV though since most 'chutes I've seen spec at ~140kts = 160mph/260kph.

I'm sure you'd have no problem getting a parachute opening spec at something like 350kph if you had to.

The problem will be to get as much as 7 astronauts out of the hatch in time.

[docmordrid]

Why blow that tiny side hatch? Couldn't they blow the much larger CBM & exit the top? Or both?

[Robotbeat]

Have to free-fall a bit to slow to a normal human TV though since most 'chutes I've seen spec at ~140kts = 160mph/260kph.

I'm sure you'd have no problem getting a parachute opening spec at something like 350kph if you had to.

The problem will be to get as much as 7 astronauts out of the hatch in time.

Quite true. Unless you split the capsule in half, I don't see how 7 could exit in time (after the main chutes failed but before hitting the water). For one or two or maybe even three, it might be possible.

A Vostok repeat could be done. Better to just ensure the main chutes work.

[docmordrid]

Repeat: blow the CBM

[SpacexULA]

Repeat: blow the CBM

before that, why not just have a backup set of chutes inside the vehcile itself, if the mains don't deploy, blow the hatch and deploy chute from inside the vehicle. 

I thought all systems on a "man rated" spacecraft had to be triple failure tollerant, so, are there already backup chute systems designed into Orion/Soyuz today?

[savuporo]

Have to free-fall a bit to slow to a normal human TV though since most 'chutes I've seen spec at ~140kts = 160mph/260kph.

Erm. I have done headdown dives at near 300kph, and have no problems braking down from there to a normal box position and deploying at regular 170kph.

[Lars_J]

Repeat: blow the CBM

Manned Dragon won't have a CBM. The docking hatch will have a much smaller diameter.

[savuporo]

Have to free-fall a bit to slow to a normal human TV though since most 'chutes I've seen spec at ~140kts = 160mph/260kph.

I'm sure you'd have no problem getting a parachute opening spec at something like 350kph if you had to.

The problem will be to get as much as 7 astronauts out of the hatch in time.

7 skydivers can exit a plane in 2-3 seconds. Even with this being more difficult in freefall, if you start jumping at 15000feet ( regularly considered safe jumping altitude ) that gives you quite a bit of time to get out.

[Chandonn]

Manned Dragon won't have a CBM. The docking hatch will have a much smaller diameter.

Acually, I'm not sure if they will have a CBM or not.  There may be a simple CBM-to-LIDS adapter on manned Dragon -- just to keep the designs as similar as possible.

[Robotbeat]

Manned Dragon won't have a CBM. The docking hatch will have a much smaller diameter.

Acually, I'm not sure if they will have a CBM or not.  There may be a simple CBM-to-LIDS adapter on manned Dragon -- just to keep the designs as similar as possible.

And with a "lifeboat Orion," there isn't a requirement to be able to undock/unberth without station power.

This is starting get off-topic, and it's my fault.

What do people give odds for successful reentry and recovery of COTS Demo 1 Dragon, assuming it gets to orbit?