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.
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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.
Readers!
Please consider supporting my work here at Behind the Black. Your support allows me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Only now does it appear that Washington might finally recognize this reality.
In 2020 when the world panicked over COVID I wrote that the panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
You can support me either by giving a one-time contribution or a regular subscription. There are four ways of doing so:
1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.
2. Patreon: Go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation.
3. A Paypal Donation or subscription:
4. Donate by check, payable to Robert Zimmerman and mailed to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage or shown in the menu above.
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.