SpaceX Dragon 2 Updates and Discussion - Thread 3

[daedalus1]

Hi,

I'm sure this is explained somewhere but please indulge me. It's prompted by the article "SpaceX launches final Dragon 1 mission to the ISS". Does this mean that all future Dragon missions to the ISS will dock not berth? Isn't berthing somewhat preferable for cargo delivery(i thought the hatch opening was larger), or doesn't it really make that much difference?

Someone can correct me, but I don’t believe Dragon 1 ever delivered a payload that was large enough to actually require the larger berthing hatch, so it won’t really be any real loss of essential capability.

If needed Cargo Dreamchaser can still deliver larger cargo, when it comes online.

I think there was really one relatively large cargo item that I can remember Dragon sending back to Earth and it was one of the few LEE's on the Candarm2. They brought it down for refurbishment on one of the recent cargo trips. Impressive something like that could fit inside Dragon. Some people who have actually went into one of those capsules say it is like a TARDIS LOL

They also brought Robonaut 2 down for repairs and upgrades in a cargo Dragon. (It went up in a shuttle.) When it is relaunched it is going up in a Cygnus because it can’t fit through the IDA on Dragon 2.

Thanks - I stand corrected.

So there is nothing now that could bring it back down again.

[Vettedrmr]

I don't think Cargo Dragon V1 can't be flown again; it's just not part of the new contract.

[daedalus1]

I don't think Cargo Dragon V1 can't be flown again; it's just not part of the new contract.

There are only a few of them, they will probably go to museums. I very much doubt they will keep one in flight condition just in case of a need!

[Vettedrmr]

Maybe.  But the comment was that large items no longer could be brought back.  I say just build a new D1 if it's needed and a flown one isn't available.  Or maybe just dock Starship to ISS; that should carry, um, well, just about anything short of a module! 

Have a good one,
Mike

[bulkmail]

Hi,

I'm sure this is explained somewhere but please indulge me. It's prompted by the article "SpaceX launches final Dragon 1 mission to the ISS". Does this mean that all future Dragon missions to the ISS will dock not berth? Isn't berthing somewhat preferable for cargo delivery(i thought the hatch opening was larger), or doesn't it really make that much difference?

Someone can correct me, but I don’t believe Dragon 1 ever delivered a payload that was large enough to actually require the larger berthing hatch, so it won’t really be any real loss of essential capability.

If needed Cargo Dreamchaser can still deliver larger cargo, when it comes online.

I think there was really one relatively large cargo item that I can remember Dragon sending back to Earth and it was one of the few LEE's on the Candarm2. They brought it down for refurbishment on one of the recent cargo trips. Impressive something like that could fit inside Dragon. Some people who have actually went into one of those capsules say it is like a TARDIS LOL

They also brought Robonaut 2 down for repairs and upgrades in a cargo Dragon. (It went up in a shuttle.) When it is relaunched it is going up in a Cygnus because it can’t fit through the IDA on Dragon 2.

Thanks - I stand corrected.

So there is nothing now that could bring it back down again.

SNC DreamChaser? I read somewhere that it can bring back the bigger stuff that goes via Dragon1 now.

[obi-wan]

Hi,

I'm sure this is explained somewhere but please indulge me. It's prompted by the article "SpaceX launches final Dragon 1 mission to the ISS". Does this mean that all future Dragon missions to the ISS will dock not berth? Isn't berthing somewhat preferable for cargo delivery(i thought the hatch opening was larger), or doesn't it really make that much difference?

Someone can correct me, but I don’t believe Dragon 1 ever delivered a payload that was large enough to actually require the larger berthing hatch, so it won’t really be any real loss of essential capability.

If needed Cargo Dreamchaser can still deliver larger cargo, when it comes online.

I think there was really one relatively large cargo item that I can remember Dragon sending back to Earth and it was one of the few LEE's on the Candarm2. They brought it down for refurbishment on one of the recent cargo trips. Impressive something like that could fit inside Dragon. Some people who have actually went into one of those capsules say it is like a TARDIS LOL

They also brought Robonaut 2 down for repairs and upgrades in a cargo Dragon. (It went up in a shuttle.) When it is relaunched it is going up in a Cygnus because it can’t fit through the IDA on Dragon 2.

Do you think it can fit through Cygnus hatch? Cygnus hatch isn't like Dragon 1's hatch, it is smaller and doesn't take up the entire CBM like D1 does

It's still way larger than the restricted passageway through the IDA, and R2 in its packaging does fit through the Cygnus hatch.

[russianhalo117]

Hi,

I'm sure this is explained somewhere but please indulge me. It's prompted by the article "SpaceX launches final Dragon 1 mission to the ISS". Does this mean that all future Dragon missions to the ISS will dock not berth? Isn't berthing somewhat preferable for cargo delivery(i thought the hatch opening was larger), or doesn't it really make that much difference?

Someone can correct me, but I don’t believe Dragon 1 ever delivered a payload that was large enough to actually require the larger berthing hatch, so it won’t really be any real loss of essential capability.

If needed Cargo Dreamchaser can still deliver larger cargo, when it comes online.

I think there was really one relatively large cargo item that I can remember Dragon sending back to Earth and it was one of the few LEE's on the Candarm2. They brought it down for refurbishment on one of the recent cargo trips. Impressive something like that could fit inside Dragon. Some people who have actually went into one of those capsules say it is like a TARDIS LOL

They also brought Robonaut 2 down for repairs and upgrades in a cargo Dragon. (It went up in a shuttle.) When it is relaunched it is going up in a Cygnus because it can’t fit through the IDA on Dragon 2.

Thanks - I stand corrected.

So there is nothing now that could bring it back down again.

Dream Chaser uses CBM and be stowed inside DC itself.

[ThomasGadd]

What is the largest volume that can be brought up in a D2's trunk? 

[Lars-J]

What is the largest volume that can be brought up in a D2's trunk?

Something like BEAM perhaps? (see image)

[Tommyboy]

What is the largest volume that can be brought up in a D2's trunk?

Something like BEAM perhaps? (see image)

My first thought as well, but after reading the question again, I *think* ThomasGadd is asking how the Dragon 2 trunk compares to the Dragon 1 trunk regarding payload volume.

[docmordrid]

What is the largest volume that can be brought up in a D2's trunk?

Something like BEAM perhaps? (see image)

My first thought as well, but after reading the question again, I *think* ThomasGadd is asking how the Dragon 2 trunk compares to the Dragon 1 trunk regarding payload volume.

Wiki reports Dragon 1's Trunk was 14 m3 standard & 34 m3 extended - IDK if the extended Trunk ever flew.

https://en.m.wikipedia.org/wiki/SpaceX_Dragon

SpaceX's Dragon 2 page reports a 37 m3 Trunk

https://www.spacex.com/dragon

[gongora]

What is the largest volume that can be brought up in a D2's trunk?

Something like BEAM perhaps? (see image)

My first thought as well, but after reading the question again, I *think* ThomasGadd is asking how the Dragon 2 trunk compares to the Dragon 1 trunk regarding payload volume.

Wiki reports Dragon 1's Trunk was 14 m3 standard & 34 m3 extended - IDK if the extended Trunk ever flew.

https://en.m.wikipedia.org/wiki/SpaceX_Dragon

SpaceX's Dragon 2 page reports a 37 m3 Trunk

https://www.spacex.com/dragon

That 14m^3 figure was from a 2009 document and showed usable payload volume in the trunk on a DragonLab mission.  I'm not sure that 37m^3 figure for Dragon 2 is actually the usable payload volume.

https://www.spacex.com/news/2013/03/26/dragon-trunk shows Dragon 1 trunk as 2.8m tall.  Both the bottom of the Dragon and the top of the second stage poke into the interior of the trunk, and the Dragon 1 trunk is not a cylinder, it's flat on the sides where the solar arrays mount.  Dragon 2 trunk is a cylinder, not sure the inner diameter or height.

[Lars-J]

What is the largest volume that can be brought up in a D2's trunk?

Something like BEAM perhaps? (see image)

My first thought as well, but after reading the question again, I *think* ThomasGadd is asking how the Dragon 2 trunk compares to the Dragon 1 trunk regarding payload volume.

Wiki reports Dragon 1's Trunk was 14 m3 standard & 34 m3 extended - IDK if the extended Trunk ever flew.

https://en.m.wikipedia.org/wiki/SpaceX_Dragon

SpaceX's Dragon 2 page reports a 37 m3 Trunk

https://www.spacex.com/dragon

That 14m^3 figure was from a 2009 document and showed usable payload volume in the trunk on a DragonLab mission.  I'm not sure that 37m^3 figure for Dragon 2 is actually the usable payload volume.

https://www.spacex.com/news/2013/03/26/dragon-trunk shows Dragon 1 trunk as 2.8m tall.  Both the bottom of the Dragon and the top of the second stage poke into the interior of the trunk, and the Dragon 1 trunk is not a cylinder, it's flat on the sides where the solar arrays mount.  Dragon 2 trunk is a cylinder, not sure the inner diameter or height.

The 2nd stage does poke into the interior of the trunk, but not by much (see image).

Dragon 2 does seem to have a longer trunk, but I'm guessing that it extends all the way to the 2nd stage tank (unlike the D1 trunk which sits on a PAF cylinder with solar panel fairing ends) - so the 2nd stage probably extends further into the D2 trunk, making the usable volume very similar.

But it is also possible that Dragon 2 sits a bit higher, and in that case, the added trunk length (and fully circular cross section) would add a bit of volume.

[daedalus1]

Isn't there a picture of Dragon 2 trunk for comparison?

[daedalus1]

Sizing from SpaceX site picture it looks like a cylinder with outside dimensions of 4m x 4m which equates to 52 cu m. So inside volume will be somewhat less than that. 37 cu m seems about right.

[Lars-J]

Sizing from SpaceX site picture it looks like a cylinder with outside dimensions of 4m x 4m which equates to 52 cu m. So inside volume will be somewhat less than that. 37 cu m seems about right.

The outside diameter is 3.7 m.

[daedalus1]

Sizing from SpaceX site picture it looks like a cylinder with outside dimensions of 4m x 4m which equates to 52 cu m. So inside volume will be somewhat less than that. 37 cu m seems about right.

The outside diameter is 3.7 m.

Inside diameter could reasonably then be 3.5 m so vol. would be 43 cu m.
So slightly under 3.5 x 4 metres is the capacity of Dragon 2's trunk.

[obi-wan]

Sizing from SpaceX site picture it looks like a cylinder with outside dimensions of 4m x 4m which equates to 52 cu m. So inside volume will be somewhat less than that. 37 cu m seems about right.

The outside diameter is 3.7 m.

Inside diameter could reasonably then be 3.5 m so vol. would be 43 cu m.
So slightly under 3.5 x 4 metres is the capacity of Dragon 2's trunk.

Has there ever been any confirmation that Dragon 2 can carry external cargo? I don’t doubt that it can in the cargo version, but given that the trunk is part of the launch escape mass, I really wonder if they can tolerate any external cargo mass for a crewed Dragon mission.

[daedalus1]

Sizing from SpaceX site picture it looks like a cylinder with outside dimensions of 4m x 4m which equates to 52 cu m. So inside volume will be somewhat less than that. 37 cu m seems about right.

The outside diameter is 3.7 m.

Inside diameter could reasonably then be 3.5 m so vol. would be 43 cu m.
So slightly under 3.5 x 4 metres is the capacity of Dragon 2's trunk.

Has there ever been any confirmation that Dragon 2 can carry external cargo? I don’t doubt that it can in the cargo version, but given that the trunk is part of the launch escape mass, I really wonder if they can tolerate any external cargo mass for a crewed Dragon mission.

This will be for the cargo version.

[rpapo]

Has there ever been any confirmation that Dragon 2 can carry external cargo? I don’t doubt that it can in the cargo version, but given that the trunk is part of the launch escape mass, I really wonder if they can tolerate any external cargo mass for a crewed Dragon mission.

Consider that any mass in the trunk is going to reduce the possible abort acceleration.  I doubt they will use the trunk while carrying people.  When using D-2 as a cargo carrier is another question entirely.