SpaceX Crewed Dragon Circumlunar Mission

[copper8]

I hope that, somehow, an IMAX camera makes this trip.

[Coastal Ron]

I hope that, somehow, an IMAX camera makes this trip.

IMAX cameras are too big.  A RED 8K digital camera would be better, but I would imagine that VR cameras will be used a lot, as well as the ubiquitous GoPro.

The revenue from video and licensing could be substantial...

[craigcocca]

The RED is smaller, but is prone to artifacts caused by cosmic radiation. A recent IMAX documentary was shot on Station with the RED, but needed a ton of post production cleanup to deal with the cosmic radiation noise that was present in the footage. On a trip to the Moon the problem will be worse.

[MATTBLAK]

Even the IMAX film they used to use was often stored with the water bags on ISS and within the bags of cargo on Shuttle to protect them. A 4K digital camera in a polyethylene enclosure might do okay, shielding wise. Also; if the Dragon is going to have a high-gain antenna to assist TV transmissions - what kind of bandwidth and resolution could we expect; 480 or 720p semi-HD?

I remember once, back in December 2006 one time when I was using my old early-2000's vintage Canon digital camera. When I viewed some pictures back that I had taken, there were interference 'orbs' in the pictures. I heard a couple days later that there had been a big solar flare around that time! I still wonder if the camera's CCD hadn't picked up a surge in cosmic rays shortly after the storm had subsided!

[ugordan]

When I viewed some pictures back that I had taken, there were interference 'orbs' in the pictures. I heard a couple days later that there had been a big solar flare around that time! I still wonder if the camera's CCD hadn't picked up a surge in cosmic rays shortly after the storm had subsided!

Err, those blobs you imaged are very much real objects out of focus. Likely dust particles near the camera illuminated by the flash. Cosmic ray hits would cause localized pixel hits ("hot pixels"), usually single pixel hits but sometimes extended tracks depending on particle trajectory.

[MATTBLAK]

You're probably right. It's almost the only image I could find in my bunch of hard drives. I used to have a lot more, but lost many pictures in a hard drive crash some years ago - insufficient backups! However, I got many similar blobs on that camera in all sorts of lighting conditions with no flash and sometimes no flash in dim lighting, too. And quite a few of them once in a dark Boeing 747 cabin over the Pacific at more than 40,000 feet! It's only ever been that particular camera. My newer compact Canon digital has never given me that phenomenon - and I've taken far more pictures under many more conditions than that old camera.

[MATTBLAK]

Anyway - we digress...

[LouScheffer]

Could SpaceX do an Apollo 8 style mission, entering lunar orbit, and then returning to Earth later?  No, as the hardware currently exists.  But the changes are not ridiculously complex.

First, what do you need?  Looking at the numbers for Apollo 12, we see 3150 m/s for TLI, 880 m/s to enter lunar orbit, and 923 m/s to return to Earth.  So we need 4953 m/s delta-V from LEO orbit.

To get this, we can use the second stage engine (ISP=348) and the super Dracos (vacuum ISP roughly 240).  The division of labor helps even with the SuperDraco's worse ISP, since they don't need to push the empty second stage.  To make this work, we'll need about 4 tonnes of Dragon fuel.  This is more than they normally carry (1.3 tonnes) but they are only carrying two people.  This gives a total Dragon mass of 11 tonnes.  Additional technical assumptions include that they can keep the LOX from boiling, the kerosene from freezing, the electronics healthy, and supply power from the Dragon to keep the second stage alive.

The SpaceX website claims the Falcon heavy can push 13.6 tonnes to Mars.  At a good conjunction, this needs about 3500 m/s of delta-V.  Working backwards, assuming a 4.5 tonne empty second stage mass, they start with 33 tonnes of fuel.  If they are only pushing 11 tonnes instead of 13.6, they will get 3890 m/s.   This is enough for TLI and the bulk of the lunar orbit insertion.  Assuming the empty Dragon + occupants = 7 tonnes, the Dragon adds 240*9.8*ln(11/7) = 1063 m/s.  That's a total of 4953 m/s, just what is needed.  The Dragon now needs to land in the ocean since there is no delta-V left for a propulsive landing, or even an assist.

I can't see SpaceX doing this since it would not lead to anything useful for Mars, nor even a lunar landing.  But the technical changes are not massive.  They will already need to work on insulation, and surviving radiation, for their direct-to-GEO capability.  And swapping passengers for extra tanks is not unheard of.  Long ago, I few a DC-9 between islands in Hawaii.  I asked how they got it there since it does not have the range to fly from the mainland.  The pilot said they took out a few rows of seats, added a temporary fuel tank, and flew them over.

[manoweb]

The RED is smaller, but is prone to artifacts caused by cosmic radiation. A recent IMAX documentary was shot on Station with the RED, but needed a ton of post production cleanup to deal with the cosmic radiation noise that was present in the footage. On a trip to the Moon the problem will be worse.

To me it would be a feature, not a bug

[punder]

I saw something recently about an Israeli company that has come up with a radiation-reducing vest for astronauts (or tourists). Just make a vest for the camera!

[guckyfan]

I saw something recently about an Israeli company that has come up with a radiation-reducing vest for astronauts (or tourists). Just make a vest for the camera!

Doesn't help. That vest might be useful for a solar event. It won't stop GCR.

[Ric Capucho]

Use a film camera.


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[Jim]

  Additional technical assumptions include that they can keep the LOX from boiling, the kerosene from freezing, the electronics healthy, and supply power from the Dragon to keep the second stage alive.

Overlooked assumption that kills the idea is update and change second stage avionics. The same avionics that can handle a planetary window longer than 1 second.

[Ben the Space Brit]

I hope that, somehow, an IMAX camera makes this trip.

If James Cameron is, as has been speculated, one of the passengers then a professional-grade digital cinematography suite (possibly the camera on a boom mounted in the trunk feeding into recording and control apparatus in the pressure cabin) is a possible secondary payload. He's said that he wants to personally film the Moon for the third Avatar film.

[philw1776]

I hope that, somehow, an IMAX camera makes this trip.

If James Cameron is, as has been speculated, one of the passengers then a professional-grade digital cinematography suite (possibly the camera on a boom mounted in the trunk feeding into recording and control apparatus in the pressure cabin) is a possible secondary payload. He's said that he wants to personally film the Moon for the third Avatar film.

So Elon was being disingenuous when he said no one from Hollywood?

[rsdavis9]

He said "no celebrities"

[Coastal Ron]

Use a film camera.

Film takes up a prodigious amount of room, especially if you want to use IMAX film.  And then you still have radiation issues to deal with.

Digital is the only way to go, and then just deal with the radiation induced artifacts in post-processing.

[envy887]

Could SpaceX do an Apollo 8 style mission, entering lunar orbit, and then returning to Earth later?  No, as the hardware currently exists.  But the changes are not ridiculously complex.

First, what do you need?  Looking at the numbers for Apollo 12, we see 3150 m/s for TLI, 880 m/s to enter lunar orbit, and 923 m/s to return to Earth.  So we need 4953 m/s delta-V from LEO orbit.

To get this, we can use the second stage engine (ISP=348) and the super Dracos (vacuum ISP roughly 240).  The division of labor helps even with the SuperDraco's worse ISP, since they don't need to push the empty second stage.  To make this work, we'll need about 4 tonnes of Dragon fuel.  This is more than they normally carry (1.3 tonnes) but they are only carrying two people.  This gives a total Dragon mass of 11 tonnes.  Additional technical assumptions include that they can keep the LOX from boiling, the kerosene from freezing, the electronics healthy, and supply power from the Dragon to keep the second stage alive.

The SpaceX website claims the Falcon heavy can push 13.6 tonnes to Mars.  At a good conjunction, this needs about 3500 m/s of delta-V.  Working backwards, assuming a 4.5 tonne empty second stage mass, they start with 33 tonnes of fuel.  If they are only pushing 11 tonnes instead of 13.6, they will get 3890 m/s.   This is enough for TLI and the bulk of the lunar orbit insertion.  Assuming the empty Dragon + occupants = 7 tonnes, the Dragon adds 240*9.8*ln(11/7) = 1063 m/s.  That's a total of 4953 m/s, just what is needed.  The Dragon now needs to land in the ocean since there is no delta-V left for a propulsive landing, or even an assist.

I can't see SpaceX doing this since it would not lead to anything useful for Mars, nor even a lunar landing.  But the technical changes are not massive.  They will already need to work on insulation, and surviving radiation, for their direct-to-GEO capability.  And swapping passengers for extra tanks is not unheard of.  Long ago, I few a DC-9 between islands in Hawaii.  I asked how they got it there since it does not have the range to fly from the mainland.  The pilot said they took out a few rows of seats, added a temporary fuel tank, and flew them over.

It's likely easier to add tanks mounted on hard points in the trunk, and run plumbing to Dragon's service section. Using Dracos instead of SuperDracos would help as well, they appear to have a specific impulse of 300 seconds. Dragon 2 looks to have 8 forward-pointing Dracos, which could fire simultaneously to get 3.2 kN of thrust.

It would also help to brake into a highly elliptical lunar orbit instead of a circular one like Apollo 8, this reduces the delta-v and thrust requirements by nearly 50%, but gives a longer orbital period. Chandrayaan-1 used a similar LOI profile with a low-thrust hypergolic engine, burning for 15 minutes to get into a 200x7500km orbit with a period of 10.5 hours. https://en.wikipedia.org/wiki/Chandrayaan-1#Lunar_orbit_insertion

Doing both would reduce the needed delta-v to about 900 m/s, which corresponds to 10,000 kg through TLI if Dragon 2 masses 6,350 kg and carries 1,000 kg payload. This likely requires catching all three FH boosters downrange, or expending the center core.

[RoboGoofers]

Use a film camera.

Film takes up a prodigious amount of room, especially if you want to use IMAX film.  And then you still have radiation issues to deal with.

Digital is the only way to go, and then just deal with the radiation induced artifacts in post-processing.

It would be easy enough to use an array of sensors for error correction. The same pixel won't be hit on each sensor. I'm sure they could wrangle gopro or RED (or Nikon, Sony, etc.) to make a custom camera for that kind of exposure.

I wonder if the newer 'light field' cameras would deal with filtering out radiation better.

[Nomadd]

The RED is smaller, but is prone to artifacts caused by cosmic radiation. A recent IMAX documentary was shot on Station with the RED, but needed a ton of post production cleanup to deal with the cosmic radiation noise that was present in the footage. On a trip to the Moon the problem will be worse.

I think watching the film with cosmic radiation artifacts would be pretty cool.