# Presentation: 532999

## Mission Operations Working Group Report

**Angie Kelly**
**NASA/Goddard Space Flight Center**
** ****Earth Science Mission Operations Project/428**

- EOS Aura Science Team MeetingOctober 3, 2007

## Topics

**Aura to Aqua Re-phasing**
- Spacecraft & Instrument Status
- S/C Subsystems
- Recent Activities
- Anomalies
- Data Losses
- Planned Activities
- Summary

## MOWG MEETING ATTENDEES

**Aura Project:   Mark Schoeberl**
**HIRDLS:  John Barnett, John Gille, Chris Hepplewhite, Jim Craft, **
**Joanne Loh, Vince Dean, Craig Hartsough**
**MLS:  Dominick Miller, Dong Wu**
**OMI:  Pieternel Levelt, Jacques Claas, Osmo Aulamo, Phillip Durbin**
**TES:  Doug Shepard, Robert Murdock, Rob Toaz**
**GSFC ESDIS:  Alfreda Hall**
**GSFC ESMO:  Pat Johnson, Dimitrios Mantziaras, Joe Purcell, **
**David Tracewell, Bill Guit, Angie Kelly**

## REVISED AGENDA

| 8:30 | Greetings/Introduction/Agenda Review | All |
| --- | --- | --- |
| 8:35 | Aura Relocation (Re-phasing):  FD Approach and Discussion | Brian Robinson/All |
| 9:15 | EOS Aura Status | A. Kelly/B. Guit |
| 9:30 | HIRDLS | C. Hepplewhite, 
J. Craft, J. Barnett, 
T. Walton, J. Gille |
| 9:45 | MLS  | D. Miller/D. Cuddy |
| 10:00 | OMIS | J. Claas |
| 10:15 | OMI DB in Sodankyla | O. Aulamo |
| 10:30 | BREAK |  |
| 10:45 | TES | R. Murdock |
| 11:00 | SSR Auto Operations Concept | D. Mantziaras |
| 11:50 | Ground System Re-engineering Plans & Schedule | P. Johnson |
| 12:10 | Updates to Ops Agreements (afternoon splinters) | J. Purcell |
| 12:20 | Summary/Actions/Next Steps | All |
| 12:30 | LUNCH BREAK |  |

## Aura to Aqua Re-phasing

## Earth Science Afternoon Constellation(A-Train)

**OCO** mission is progressing – launch in late 2008
**Glory** is planning to join the Constellation at ~ 4 minutes behind Aqua
**Evaluating plan to move Aura about 7 minutes closer to Aqua**

**Earth Science Afternoon Constellation****(A-Train)**

| Mission | MLT |
| --- | --- |
| Aqua | 01:34:43 |
| CloudSat | 01:43:25 |
| CALIPSO | 01:43:37 |
| PARASOL | 01:33:14 |
| Aura | 01:43:39 |

- As of September 17, 2007

## 	Aura to Aqua Re-phasing

- •  M. Schoeberl requested an analysis in early 2007
- 		•• **Move Aura closer to Aqua by ~ 7 minutes**
- Phase change would decrease the amount of time between Aqua and Aura instrument measurements.
- •• **To obtain better science utilizing A-Train data**
- •  Preliminary analysis was discussed with M. Schoeberl in June and sent to Aura teams in June/July
- •  OMI operations team provided comments/concerns; discussed at telecon on 9/13/07
- •  EOS Flight Dynamics presented updated plan/options at Aura MOWG meeting on Oct 2

## Aura Re-Phasing Impacts

**• ****SAFETY:****  **
- ••  Moving Aura closer to Aqua (~7 minutes) can be implemented safely
- ••  No safety concerns with other A-Train satellites
**• ****Mission Life:****  **
- •• Moving Aura closer to Aqua involves a small amount of fuel, thus, no impact to Aura’s mission life
- 	-- Currently holding adequate fuel reserve to meet 25-year re-entry guidelines

## Current Phasing

- Current phasing is ~16 minutes in along-track separation,
- trending towards a minimum of ~15 in the next two years.

## Current Aura Orbit Requirements

- Maintain MLTAN between 13:30 and 14:00
- Due to current MLTAN phasing with Aqua and timing of inclination maneuvers, MLTAN has been maintained between 13:40 and 13:45.
- Current MLTAN is 13:44 and is trending to a minimum of ~13:42.
- Orbit +/- 20Km of the WRS-2 ground path that is 1 path + 25 Km West of Aqua at the descending node.
- Phasing of 15-22 minutes in along-track separation, but as close to 15 minutes as possible
- Current phasing is ~16 minutes in along-track separation, trending towards a minimum of ~15 in the next two years.
- Solar beta angle requirement is 16 – 36 degrees.
- OMI Request:  Maintain a solar beta angle of 18.3 to 31.2 degrees (9/13/07).

## Proposed Phasing

## Implementation Options

**Option I – Drag Option**
- Use atmospheric drag to reduce Semi Major Axis (SMA) and drift closer to Aqua.
**Option II – Inclination Maneuver Option**
- Use 2 inclination maneuvers to reduce SMA and drift closer to Aqua.

## Pros/Cons

- 1 – Best, 2 – Medium, 3 – Worst

|  | I – Drag Option
(preferred option) | II – Inclination Maneuver |
| --- | --- | --- |
| Drag Environment Dependency | 3 | 1 |
| Drift Duration | 2 | 1 |
| Analysis Required | 1 | 1 |
| Fuel Usage | 1 | 1 |
| MLTAN Profile | 1 | 1 |
| MLTAN Separation Drift Rate | 1 | 1 |
| Timeliness (Start Time) | 1 | 3 |
| Completion Date | 1 
(start date + 6-9 months) | 3 
Spring 2009 |

## FEEDBACK FROM THE 

**FEEDBACK FROM THE **
**AURA INSTRUMENT TEAMS**

| Instrument | Agree to 
Re-phasing? | Comments |
| --- | --- | --- |
| HIRDLS | Yes |  |
| MLS | Yes | 7.7 minutes is ideal for coincidental science with CloudSat (Dong Wu). |
| OMI | TBD | KNMI to determine flight software impact.
Answer due Oct 17, 2007 |
| TES | Yes |  |

## SUMMARY

**•   ****Aura re-phasing can be accomplished safely**
**•   ****Aura re-phasing will not impact mission life**
**•   ****Drag option is preferred implementation**
- •  Does not require new procedures;
- •  Can be completed by Spring 2008 (based on   December 2007 start date)
**•  ****Decision is needed by Dec 5 (next Drag Make-up    maneuver)**
**•   ****Aura re-phasing will result in better science!**

## SPACECRAFT STATUS

## Spacecraft Subsystems

**Command & Data Handling (CDH)** – Nominal
- Solid State Recorder (SSR) – holds 3 orbits of data
**Communications (COMM)** - Nominal
**Electrical Power System (EPS)** – Nominal
*Solar Panel Connector Anomaly (January 12, 2005)*
**Flight Software (FSW)** - Nominal
**Guidance, Navigation & Control (GN&C)** - Nominal
**Propulsion (PROP)** – Nominal
*Dual Thruster Module (DTM-3) Anomaly (August 16, 2005)*
**Thermal Control System (TCS)** – Nominal

_**All subsystems configured to primary hardware**_

## Recent Activities(since August 2006)

## Major Activities

- 08/16/06: – NASA HQ Review
- Aug-Sep: Inclination Adjust
- Mar-May: Inclination Adjust
- 06/12/07: Flight Ops Status Review
- 07/15/07: 3-Year Anniversary
- July-Aug: TC4 Campaign
- 07/30/07: MLS Venus Scans
- 10/02/07: MOWG (at Science Team Meeting)

## Anomalies

## Anomalies

- Spacecraft Anomalies
- No new anomalies
- Instrument Anomalies
- 10/10/06: HIRDLS Gyro 0 Anomaly
- 04/28/07 HIRDLS Gyro 3 Anomaly
- 07/14/07: MLS SIF4 Anomaly
- 08/04/07: TES Filter Wheel Anomaly
- 08/07/07: MLS Mechanism Anomaly

## Data Losses

## Data Losses

- No SSR Science Data lost since July 2006

## Planned Activities

## Planned Activities

- Aura Re-location – Timing is TBD
- HIRDLS Pitch Maneuver – Nov 6th
- SSR Auto Ops with EDOS fix (2008)
- Spring 2009 Inclination Adjust
- Aura Senior Review in 2009

## Summary

- Spacecraft Status – GREEN
- Instrument Status –  GREEN
- Operations Nominal
- Data Capture – GREEN
**SSR Data Capture  ~ 99.989 %**
- Planned Activities:
- Drag Make-up Maneuver – Dec 5 ?
- HIRDLS Pitch – Nov 6, 2007

## Questions?Thank you!

**ADDITIONAL INFORMATION**

## Option I – Drag Option

- Use atmospheric drag to reduce the SMA and initiate the forward drift.
- Stop performing Drag Make-Up (DMU) maneuvers until desired separation is attained
- Once the correct phasing is reached an orbit raising maneuver would stop the drift and establish  a new ground-track control box.
- NO change to the current MLTAN profile.

***Note:  Next DMU is ~ Dec 5***

## Option I – Drag Option Evaluation

- The duration of the re-phasing will be dictated by Aura’s position within the ground-track cycle.  Pre- and Post-DMU results are reported to indicate the additional time required to drift through the ground-track cycles of each drag environment.

## Option II – Inclination Maneuver Option

- Execute inclination maneuver that would lower the orbit in order to initiate a drift forward.
- DMUs would be halted until desired separation is attained.
- Once the correct phasing is reached an orbit raising maneuver would stop the drift and establish a new ground-track control box.
- A small change to the MLTAN would be incurred due to the use of inclination maneuvers
- The MLTAN is not expected to drift below 13:40

## Option II – Inclination Maneuver Option Evaluation

- **  Burn duration for Ground Track control only; does not include any needed inclination maneuvers.