SpaceX studying changes to de-orbit procedures for Dragon service module
Because it appears the trunk section of the service module of SpaceX’s Dragon capsules actually survives re-entry, the company is now studying changes to its de-orbit procedures so that it can guarantee that trunk will not crash on land, as has happened now three times in the past two years.
The solution [a NASA official] said NASA and SpaceX are looking at involves changing deorbiting procedures. Currently, the trunk is released before the capsule performs its orbit burn. That means the trunk can remain in orbit for months before making an uncontrolled reentry.
Instead, [that NASA official] said engineers are examining doing the deorbit burn and then releasing the trunk. That would provide more control of where the trunk reenters, ensuring that any debris that survives reentry lands in unpopulated regions.
To make this new procedure work they need to recalculate the fuel requirements for doing the de-orbit burn. It also requires them to figure out when to detach the trunk after the burn. I expect SpaceX to successfully implement these changes before the next Dragon launch, whether manned or unmanned.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
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Because it appears the trunk section of the service module of SpaceX’s Dragon capsules actually survives re-entry, the company is now studying changes to its de-orbit procedures so that it can guarantee that trunk will not crash on land, as has happened now three times in the past two years.
The solution [a NASA official] said NASA and SpaceX are looking at involves changing deorbiting procedures. Currently, the trunk is released before the capsule performs its orbit burn. That means the trunk can remain in orbit for months before making an uncontrolled reentry.
Instead, [that NASA official] said engineers are examining doing the deorbit burn and then releasing the trunk. That would provide more control of where the trunk reenters, ensuring that any debris that survives reentry lands in unpopulated regions.
To make this new procedure work they need to recalculate the fuel requirements for doing the de-orbit burn. It also requires them to figure out when to detach the trunk after the burn. I expect SpaceX to successfully implement these changes before the next Dragon launch, whether manned or unmanned.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
This may be a very dumb question, but have they considered the possibility of re-engineering the service module (changing materials, lightening the structure, etc.) so that it DOES burn up completely on re-entry? It would appear to a non-space engineer that it may be somewhat over-built for its function as currently designed.
Blackwing1: I am no engineer, but I think SpaceX’s proposed solution is the simpliest and fastest to implement. Also, the trunk is used as a cargo area for bringing up material that doesn’t need to be in a pressurized protected capsule. I suspect this is why it is built so robustly, to protect that material during launch. SpaceX will not wish to lose that capability.
“… the trunk is released before the capsule performs its orbit burn.”
Do they mean de-orbit burn here? (If it is a mistake, I assume it was in the original quotation.)
What we need is a salvage yard up there. Leave the service modules up there, and then melt them down. Once Starship starts flying, put in place a treaty, that takes into effect 5 years after Starship is in service. This treaty says that all spacecraft, have to be reusable, if they are launched from Earth. But again, this would take effect 5 years after Starship is in service, and is delivering cargo, passenger’s, to LEO, and beyond.
I can think of two drawbacks off the top of my head. The first is the larger fuel requirement for the de-orbit burn due to the increased mass. The second is that once the burn is accomplished, you are on the clock to detach the trunk (and achieve proper attitude) before entry. Both of these seem manageable risks given the experience with the hardware.