Download presentation

Presentation is loading. Please wait.

Published byAlex Combs Modified over 3 years ago

1
1 GOES-12 Eccentricity Control (Co-Location with Brasilsat B1) Richard McIntosh a.i. solutions, Inc. AIAA SOSTC Workshop April 15, 2008

2
2 Co-Location Requirements GOES-12 located at 75 deg W +/- 0.5 deg longitude. Brasilsat B1 given OK to move from 70 deg W to 75 deg W and maintain +/- 0.1 deg longitude. B1 now occupies the middle 0.2 deg of GOES-12 box. StarOne (B1 owners) suggested eccentricity vector control to avoid close approaches. GOES maneuver control software not capable of planning East- West stationkeeping (EWSK) maneuvers that include eccentricity vector control. NOAA desires to not perform any extra maneuvers for eccentricity control. Analysis performed to determine how eccentricity control could be incorporated into the normal 1-burn EWSK operations.

3
3

4
4 Eccentricity Control Strategy Recommended By StarOne Eccentricity Vector ex = e cos(Ω+ω) ey = e sin(Ω+ω)

5
5 V V ECC VECTOR ΔV from SRP Raises Apogee ΔV from SRP Lowers Perigee SRP Effect of Solar Radiation Pressure on Eccentricity

6
6 EX = e cos(Ω+ω) EY = e sin(Ω+ω) Natural Eccentricity Circle (size depends on Area/Mass)

7
7

8
8 Eccentricity Control Eccentricity vector will tend to follow the natural circle throughout the year. Desired control circle size is usually smaller. Objective is to try to make a short arc of the natural circle closely follow the control circle over the next EWSK cycle. EWSK frequency: –GOES-12every 11 or 12 weeks –B1every 3 weeks

9
9 β β Control Circle Natural Circle Δα Δα = Change in Sun RA over 1 East-West Maneuver Cycle Sun at Start Sun at End EX EY

10
10 ΔeΔe Control Circle Natural Circle Δα β β EY EX Next E-W Cycle

11
11 Equations (1 of 3)

12
12 Equations (2 of 3) ΔeΔe RA1

13
13 Equations (3 of 3) Note: Delta-Vs are normally in negative velocity direction for 75 West

14
14 1-Burn vs 2-Burn Control 1-Burn -0.268 m/s 2-Burns -0.478 and +0.211 m/s

15
15 Single Burn at Perigee

16
16 2-Burn Control 0.0003 Circle

17
17 2-Burn Control 0.0002 Circle

18
18 GOES-12 4-Year Simulation 1-Burn East-West Maneuvers

19
19

20
20

21
21

22
22

23
23

24
24 Conclusions Analysis has shown that sufficient eccentricity control can be accomplished by GOES-12 with little or no impact to the normal EWSK operations (single-burn). Only requirement is a change in the time of the burn (move from the normal perigee burn location). NOAA has incorporated the equations presented here into a spreadsheet that computes the nominal time of the burn. GOES-12 successfully performed the first EWSK maneuver with eccentricity control on July 24, 2007. Subsequent EWSK maneuvers have shown that the single-burn strategy provides adequate eccentricity control. Further analysis needs to be done to verify that the desired spacecraft separation can be maintained in the long term.

Similar presentations

OK

© Charles van Marrewijk, 2003 1 An Introduction to Geographical Economics Brakman, Garretsen, and Van Marrewijk.

© Charles van Marrewijk, 2003 1 An Introduction to Geographical Economics Brakman, Garretsen, and Van Marrewijk.

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on types of sentences Ppt on cross multiplication method of linear equations Ppt on standing order act score Flexible display ppt on ipad Ppt on minimum wages act 1948 Ppt on trial and error supernatural Ppt on 3 idiots movie last part Ppt on indian entertainment and media industry Ppt on cartesian product sql Ppt on index numbers in mathematics