F9/Crew Dragon : Polaris Dawn : KSC LC-39A : 10 Sep 2024 (09:23 UTC) DISCUSSION

[Comga]

The first flight, which could come by the end of the year, will aim to send a crew of four farther than any other human spaceflight in 50 years

So they go far but not as far as the Moon (would have required FH). Minimum apogee to meet this is goal is maybe 600km?
(snip)

Could they be going for the Gemini 11 record of 1,300 km?  Not sure how much margin the F9 has for Crew Dragon launches. 
(snip)
Really looking forward to the mission and hopefully another Netflix series!!!!   

Can’t F9 get Crew Dragon up to maximum of a 1000 Km orbit?

LSP website says the payload to 1300 km circular is 12,270 kg, which is right around what Crew Dragon masses. Payload to an elliptical orbit would be a bit higher, though. F9 might be able to push an apogee nearer 2000 km.

Dragon also has a lot of onboard propellant available for maneuvering, too.

The Polaris Dawn website says that the EVA will be conducted "at 500 km". (edited. Thanks scr00chy)
That's reasonable, as it might be an issue to do an EVA with exposure to the lower edge of the Van Allen Belts, which IIRC starts around 1000 km.
This implies that the mission will have two phases, an elliptical orbit with a high apogee and a circular orbit at 500 km.
There will be available all the propellants carried for the SuperDraco LAS.
If one adds in either a burn to raise or lower the apogee from 500 km circular, what would be the maximum reachable altitude?

[yg1968]

Ok so it sounds like they will use enhanced IVA suits for this mission that can also function as EVA suits. (Again like Gemini)

I imagine that these suits are half way between an IVA suit and the bulkier spacesuits than astronauts use at the ISS. Right?

[scr00chy]

The first flight, which could come by the end of the year, will aim to send a crew of four farther than any other human spaceflight in 50 years

So they go far but not as far as the Moon (would have required FH). Minimum apogee to meet this is goal is maybe 600km?
(snip)

Could they be going for the Gemini 11 record of 1,300 km?  Not sure how much margin the F9 has for Crew Dragon launches. 
(snip)
Really looking forward to the mission and hopefully another Netflix series!!!!   

Can’t F9 get Crew Dragon up to maximum of a 1000 Km orbit?

LSP website says the payload to 1300 km circular is 12,270 kg, which is right around what Crew Dragon masses. Payload to an elliptical orbit would be a bit higher, though. F9 might be able to push an apogee nearer 2000 km.

Dragon also has a lot of onboard propellant available for maneuvering, too.

The Polaris Dawn website says that the EVA will be conducted "at 300 km".
That's reasonable, as it might be an issue to do an EVA with exposure to the lower edge of the Van Allen Belts, which IIRC starts around 1000 km.
This implies that the mission will have two phases, an elliptical orbit with a high apogee and a circular orbit at 300 km.
There will be available all the propellants carried for the SuperDraco LAS.
If one adds in either a burn to raise or lower the apogee from 300 km circular, what would be the maximum reachable altitude?

500 km, not 300 km

[envy887]

The first flight, which could come by the end of the year, will aim to send a crew of four farther than any other human spaceflight in 50 years

So they go far but not as far as the Moon (would have required FH). Minimum apogee to meet this is goal is maybe 600km?
(snip)

Could they be going for the Gemini 11 record of 1,300 km?  Not sure how much margin the F9 has for Crew Dragon launches. 
(snip)
Really looking forward to the mission and hopefully another Netflix series!!!!   

Can’t F9 get Crew Dragon up to maximum of a 1000 Km orbit?

LSP website says the payload to 1300 km circular is 12,270 kg, which is right around what Crew Dragon masses. Payload to an elliptical orbit would be a bit higher, though. F9 might be able to push an apogee nearer 2000 km.

Dragon also has a lot of onboard propellant available for maneuvering, too.

The Polaris Dawn website says that the EVA will be conducted "at 300 km".
That's reasonable, as it might be an issue to do an EVA with exposure to the lower edge of the Van Allen Belts, which IIRC starts around 1000 km.
This implies that the mission will have two phases, an elliptical orbit with a high apogee and a circular orbit at 300 km.
There will be available all the propellants carried for the SuperDraco LAS.
If one adds in either a burn to raise or lower the apogee from 300 km circular, what would be the maximum reachable altitude?

They need about 290 m/s to go from 300 km circular to 300 x 1400 km. Dragon should have at least twice that available if they use the abort propellants through the RCS.

[whitelancer64]

Ok so it sounds like they will use enhanced IVA suits for this mission that can also function as EVA suits. (Again like Gemini)

I imagine that these suits are half way between an IVA suit and the bulkier spacesuits than astronauts use at the ISS. Right?

As said earlier, we have almost no details yet. IMO, most likely, they will be modified IVA suits. They will use an umbilical, so they don't need a life support backpack or a SAFER type system. At minimum, they will need more thermal insulation and visors to protect from the intensity of the Sun's light. Depending on what they want to do during the EVA, they may need more dexterity in the gloves.

[yg1968]

Ok so it sounds like they will use enhanced IVA suits for this mission that can also function as EVA suits. (Again like Gemini)

I imagine that these suits are half way between an IVA suit and the bulkier spacesuits than astronauts use at the ISS. Right?

As said earlier, we have almost no details yet. IMO, most likely, they will be modified IVA suits. They will use an umbilical, so they don't need a life support backpack or a SAFER type system. At minimum, they will need more thermal insulation and visors to protect from the intensity of the Sun's light. Depending on what they want to do during the EVA, they may need more dexterity in the gloves.

I think that describing it as a modified IVA suit is correct. During the press conference, they called them upgrades to the existing SpaceX IVA suits and the image that you posted above also appears to show that:

https://twitter.com/SpcPlcyOnline/status/1493270944433025034

See also:
https://forum.nasaspaceflight.com/index.php?topic=55805.msg2341299#msg2341299

[billh]

I seem to recall from years ago that NASA required the commercial crew spacecraft to be operable for some number of hours after a complete loss of cabin pressure, to allow time for an abort from orbit. So there is no need for an airlock to do an EVA, as long as its duration doesn't exceed the design spec for operation in a vacuum.

They mention studying the effects of decompression sickness. I wonder how they will manage a transition to a full oxygen / lower pressure environment for this EVA. Maybe take the whole cabin to 3psi 100% O2 over a period of hours, then suit up and evacuate the cabin?

[jpo234]

Maybe take the whole cabin to 3psi 100% O2 over a period of hours

Does the existing Dragon ECLSS support this? I kind of doubt that...

[Robotbeat]

Maybe take the whole cabin to 3psi 100% O2 over a period of hours

Does the existing Dragon ECLSS support this? I kind of doubt that...

you don’t need to be that extreme. Shuttle supported a similar measure to reduce prebreathe time.

[akm]

A private space missions with EVAs and start ships starting within a year.  This counts as proper awesome !!! 

[cohberg]

Maybe take the whole cabin to 3psi 100% O2 over a period of hours

Dragon carries significantly more premixed nitrox than O2. I'm not sure there is enough to flush the ship with pure O2 then return it to normal composition. Additionally, I'm not sure you would want a pure O2 environment for the entire ship due to fire risk for any significant period.

Shuttle supported a similar measure to reduce prebreathe time.

Huh TIL about shuttle EVA prep. However the shuttle didn't alter the atmospheric composition to pressures that low and pure O2.

One solution was to lower shuttle cabin pressure from its nominal pressure of 101.2 kPa (14.7 psi) to 70.3 kPa (10.2 psi) for at least 12 hours prior to the EVA. This reduced cabin pressure protocol was efficient and effective, with only 40 minutes prebreathe.

This sounds very plausible for Dragon. The firefighting / leak modes already have programming and valving to be able to maintain lower set point (8 psi) pressures. 10 psi (starting during a sleep period and into the next day for ~12 hours) sounds easy / ideal.

The last 40 minutes could be done in the EVA / IVA suit or with a o2 mask plugged into the buddy breath port which is already plumbed for pure O2.

[Herb Schaltegger]

Maybe take the whole cabin to 3psi 100% O2 over a period of hours

Does the existing Dragon ECLSS support this? I kind of doubt that...

you don’t need to be that extreme. Shuttle supported a similar measure to reduce prebreathe time.

Shuttle required more total pressure, however, even if it could be reduced (~10 psi? It's been a long time since I needed to know this stuff for my job). That's because too much of the avionics thermal load was carried by air-cooling. Station, by contrast, was designed from the outset for much more (nearly 100%) total avionics and system heat load to be carried by coldplates and then rejected by the ETCS radiators.

[AS_501]

If I understand correctly, the umbilical provides life support (akin to Skylab), thus no back pack that could cause hatch clearance problems.  Also, does SpaceX have its own NBL?

[daveglo]

... They will use an umbilical, so they don't need a life support backpack or a SAFER type system....

You'd think they'll need SOMETHING for attitude control, unless we see some kind of handhold arrangement appearing on the outside of Dragon?  Got to have something for the tethers to hang onto.

It's cooler view than the I4 cupola, but two heads out the hatch are going to bang into one another a lot without some positional management.

It will be interesting to hear about goals for the EVA.  Is it just to prove out a new suit and air management procedures?  Are they going to be able to reach the trunk?  The image of the patch looks like the trunk has something poking out of it?  A low-budget arm?

This is going to be fascinating to watch develop.

[whitelancer64]

... They will use an umbilical, so they don't need a life support backpack or a SAFER type system....

You'd think they'll need SOMETHING for attitude control, unless we see some kind of handhold arrangement appearing on the outside of Dragon?  Got to have something for the tethers to hang onto.

It's cooler view than the I4 cupola, but two heads out the hatch are going to bang into one another a lot without some positional management.

It will be interesting to hear about goals for the EVA.  Is it just to prove out a new suit and air management procedures?  Are they going to be able to reach the trunk?  The image of the patch looks like the trunk has something poking out of it?  A low-budget arm?

This is going to be fascinating to watch develop.

I would fully expect the Dragon and its trunk to be modified for this mission with handrails and / or other clip on points at strategic locations. One or both of them free-floating in front of the Dragon is unlikely, IMO, I would consider that artistic license (but if it happened they could use the umbilical to pull themselves back in). We don't know what the purpose of the EVA is yet, so beyond that it's harder to guess.

[whitelancer64]

Better image of the Polaris Dawn render:

[Solariss]

Sorry for possible offtopic, but this mission may be a nice advertisement for Dragon's EVA support capabilities for NASA. After SpaceX demonstrate that they indeed can support such missions  wouldn't it be lucrative for NASA to use D2 to repair  Hubble?

[Robotbeat]

Sorry for possible offtopic, but this mission may be a nice advertisement for Dragon's EVA support capabilities for NASA. After SpaceX demonstrate that they indeed can support such missions  wouldn't it be lucrative for NASA to use D2 to repair  Hubble?

the usual comment is that Hubble has seen its last servicing mission and JWST and later telescopes will be the replacement instead. But…

https://spacecraft.ssl.umd.edu/akins_laws.html

“38. Capabilities drive requirements, regardless of what the systems engineering textbooks say.“

[Oersted]

SpaceX and Isaacman aren't just pushing the envelope. They're positively running it through the paper shredder!

[tacoLover7916]

This is awesome. It’s so exciting to see more private flights on the horizon.

If I’m not mistaken this would make Isaacman the first to fly on Dragon twice!