Author Topic: Orbital ATK ready for Cygnus flights this year and first CRS-2 mission  (Read 2893 times)

Online Chris Bergin

https://www.nasaspaceflight.com/2018/01/cygnus-flights-year-first-crs-2-contracted-mission/

By Chris Gebhardt interviewing Orbital ATK's Frank DeMauro.

L2 Renders by Nathan Koga

Online yg1968

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Good article! Nice to hear about their progress on CRS2.

Online Chris Bergin

Follow up included in this ISS article:
FEATURE ARTICLE: Station science excellent; Commercial Cargo-2 contracts making good strides -

https://www.nasaspaceflight.com/2018/04/station-science-commercial-cargo-2-contracts-strides/

- By Chris Gebhardt

Offline Comga

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Interesting note from the post flight press conference.  Cygnus will perform a small re-boost of the station. 
A followup question indicated no Dragon reboost capability is planned.

This is mentioned in the article.
Any details on that?
How is the ISS oriented for a Cygnus re-boost, and what is the load path?
Cygnus pushing on the Node-1 Zenith CBM would impart torque on the whole ISS.
edit: It's not a lot of torque on the joints from a structural standpoint.
Do they just store up a lot of opposing angular momentum ahead of time?
And how long do they plan to fire the 450 N main engine to get a significant reboost?
That's approximately 1 mm/sec^2, or 1E-4 g for the 420 tonne ISS.

One would also think it would be so much easier to reboost with Dragon-2 docked facing along the length of the ISS backbone from Node 1 to Zarya.  They could yaw or pitch the ISS around by 180 degrees and use the backward facing 71 kN Super Dracos if they didn't want to use the multiple 400 N Dracos that are pointed somewhat along the line of the modules. 
« Last Edit: 05/21/2018 05:17 PM by Comga »
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline deruch

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Interesting note from the post flight press conference.  Cygnus will perform a small re-boost of the station. 
A followup question indicated no Dragon reboost capability is planned.

This is mentioned in the article.
Any details on that?
How is the ISS oriented for a Cygnus re-boost, and what is the load path?
Cygnus pushing on the Node-1 Zenith CBM would impart torque on the whole ISS.
edit: It's not a lot of torque on the joints from a structural standpoint.
Do they just store up a lot of opposing angular momentum ahead of time?
And how long do they plan to fire the 450 N main engine to get a significant reboost?
That's approximately 1 mm/sec^2, or 1E-4 g for the 420 tonne ISS.

One would also think it would be so much easier to reboost with Dragon-2 docked facing along the length of the ISS backbone from Node 1 to Zarya.  They could yaw or pitch the ISS around by 180 degrees and use the backward facing 71 kN Super Dracos if they didn't want to use the multiple 400 N Dracos that are pointed somewhat along the line of the modules.

In addition to technical considerations of using D2, you'd also have to consider the question of whether it is better for the disruption of the investigations in a microgravity environment to be low force x long period or high force x short period.
Shouldn't reality posts be in "Advanced concepts"?  --Nomadd

Offline bulkmail

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In the OA9 article is written that C2V2 (Common Communications for Visiting Vehicles) is "an effort to streamline communications for all visiting vehicles to the USOS (U.S. Operating Segment)"

Cygnus is already using it.
Dragon v2 (crew & cargo) and CST-100 apparently will use it as well.
DreamChaser - I assume so (but hasn't seen it mentioned).
Dragon v1 - to stop flying after 20th CRS mission, so not to be updated to C2V2?
HTV / HTV-X - what about those?

PS. Not really Cygnus questions, so please move to a more appropriate place if needed.

Offline deruch

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In the OA9 article is written that C2V2 (Common Communications for Visiting Vehicles) is "an effort to streamline communications for all visiting vehicles to the USOS (U.S. Operating Segment)"

Cygnus is already using it.
Dragon v2 (crew & cargo) and CST-100 apparently will use it as well.
DreamChaser - I assume so (but hasn't seen it mentioned).
Dragon v1 - to stop flying after 20th CRS mission, so not to be updated to C2V2?
HTV / HTV-X - what about those?

PS. Not really Cygnus questions, so please move to a more appropriate place if needed.

-DreamChaser will definitely be using C2V2.  (I believe it was a requirement for the CRS2 contracts.)

-Dragon v1 still uses the CUCU (COTS UHF Communication Unit) system.  I don't know if they have any plans to change over to C2V2 with that vehicle or just let it get phased out when the switch over to Dragon 2 and CRS2/CC happens.

-HTV currently uses PROX, which is the JAXA designed system put in place specifically for HTV rendezvous.  It uses antennas and radios that run through Kibo.  That system was what Cygnus was using on prior missions before now switching over to C2V2.  I haven't heard anything about HTV using C2V2, and I sort of doubt it will.  But who knows, I might be wrong.
« Last Edit: 05/24/2018 02:36 PM by deruch »
Shouldn't reality posts be in "Advanced concepts"?  --Nomadd

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