CRaTER Project Monthly Technical Progress and Schedule Status Report (NNG05EB92C DRD 20 & 21) May 2005

Transcription

1 CRaTER Project Monthly Technical Progress and Schedule Status Report (NNG05EB92C DRD 20 & 21) May 2005 Page 1 of 6

2 Table of Contents Project Scientist s Report... 3 Project Engineer s Report... 3 Mission Assurance Manager s Report... 4 Program Manager s Report... 4 Schedule Status... 5 Meetings & Telecoms... 5 Budget & Manpower Status...5 Risk Analysis... 6 Page 2 of 6

3 Project Scientist s Report Project science work in the April 2005 period consisted of characterizing the expected radiation environment during the mission, feeding back these predictions into the instrument design and preparing for the PDR in June. The status of these studies was presented at the first CRaTER TIM at MIT on April 14. In order to characterize the expected range and intensity of energetic particle fluxes in the lunar environment we have separated the sources into four categories: Galactic Cosmic Ray (GCR), Solar Energetic Particles (SEP), magnetospheric (MS) and in the foreshock (FS) region upstream of the Earth s bow shock. The GCR flux in the CRaTER energy range is expected to vary slowly over the course of the 11 year solar cycle by factors of a few and the typical GCR count rate in the front detector system is expected to be several events per second. For SEPs we have modeled the particles of the January solar flare, as observed by the Wind and ACE spacecraft. The observed fluxes were fit with power law distributions in energy and combined with a simple model of the CRaTER telescope to produce predicted rates in each detector as a function of materials used in the instrument. Our initial estimates are that the low energy end of the spectrum during the peak intensity of the flare would have led to count rates of approximately 1400 events per second. This is slightly above our planned maximum event rate, but well below the point where we would be concerned about multiple particles depositing energy in a detector during a single pulse height analysis. We used archived data from several Earth orbiting spacecraft to model the typical intensities of MS and FS particles, and learned that the FS particles will dominate. The integral counting rate for FS particles in the lowest energy detector would be on the order of 10 events a second during portions of the lunar orbit when the moon and LRO are upstream of the Earth and magnetically connected to the bow shock. We have been considering the use of a metal collimator to reduce the field of view of lower energy particles that enter the telescope and deposit in detectors D1 and D2 and the affect of different shield thicknesses above D1 on the overall event rate. The results of these simulations will be used to identify the optimum shield and collimator properties. Currently the Boston group is using programs written in IDL to simulate the telescope performance. We intend to perform some of these calculations in GEANT on a new computer system at Boston University. Our calculations have also led us to the conclusion that 35mm diameter detectors are preferable over 25mm detectors. We have produced a draft CRaTER data processing document and provided feedback on the drafting of the Level 1 measurement objectives. Currently we have begun work on the Level 2 description of CRaTER measurement objectives and requirements, in preparation for the PDR. Project Engineer s Report Work has begun on establishing the basic design of the Electrical GSE needed to support CRaTER. Our current hardware vision is for a small, self-contained "headless" workstation with a commercial 1553B interface card, which establishes a socket interface over the Internet to both the command and telemetry packets. This CCSDS packet interface is identical to that implemented by the spacecraft C&DH system, and what we assume will also be the interface to the real-time telemetry interface during flight. Additional electrical hardware consists of a one Hertz clock pulser and >10 watt 28VDC adjustable power supply. Page 3 of 6

4 A review of the original proposal's electrical design resulted in a major perturbation in our power budget. Although the analog section has not changed significantly in power consumption, the digital section has changed in several ways. Firstly the 1553B interface to the spacecraft is -- of all possible standard interfaces -- the most power hungry of the bunch. On the other hand our current design does not require a DPU, which reduces demand. The overhead requirements of the low voltage power converters had not been properly included in the original proposal (difficult to do without a more detailed design), which added to the required bus current. Finally, a brief search of available radiation-hardened A/D converters turned up no suitable low-power choices. On the worst day of the month, our best estimate power consumption shot up from 4.6 watts to 7 or 8 watts. By month's end the numbers were trending downward again, but more work remains to be done. A technical interchange meeting between Aerospace and MIT on April 13 helped to establish a good working relationship between the mechanical and electrical engineers. A TIM with GSFC on the following day was especially useful in resolving mechanical accommodation issues, giving CRaTER a clear field of view in excess of our 30 degree full angle requirement in the Zenith direction and 80 degree full angle in the Nadir direction. We also worked a number of minor issues with respect to the Data ICD (which is far ahead of all our other ICDs). The Data ICD now calls for the spacecraft to retrieve primary science telemetry packets from CRaTER every 25ms (nominally 100Kbps), and to strip out fill bits and fill packets prior to forwarding the data to the on-board recorder. Mission Assurance Manager s Report Brian Klatt, Bob Goeke and Rick Foster met with Ron Kolecki (NASA-GSFC Mission Assurance Manager) regarding the differences between the Proposal Information Package (PIP) and the Draft Performance Assurance Implementation Plan (PAIP). Ron provided many useful clarifications on what NASA expected from the CRaTER Project. Brian started rewriting the CRaTER PAIP based on the clarifications resulting from the meeting with Ron. This new PAIP is more than 75% done on the first pass. The next big step, prior to our PDR submittal, is to review the CRaTER PAIP soon with Aerospace Corporation, with the intention of them incorporating the PAIP into their CRaTER activities. Pilar Joy is the Materials Engineer at GSFC coordinating the testing of A-150 Tissue Equivalent Plastic (TEP) for the Crater Project. She has asked for more sample material. This has been sent out. Chris Sweeney of B.U suggested getting a sample of Bone Equivalent Plastic (BEP) as a potential alternate to TEP, should it have undesirable properties. Brian Hooten at Standard Imaging was contacted and has supplied the BEP sample. However, based upon a verbal report from Pilar, it appears that the TEP will not be a problem from offgassing. We are awaiting the final formal report, expected by 5/23/05. Program Manager s Report Getting the Aerospace Corp subcontract in place was the major programmatic event for this period. The final (relatively small) subcontract with University of Tennessee should be in place next month. Improvement has been made in getting the project consolidated financials reporting streamlined culminating with the generation of this month s 533M report. With this month s Page 4 of 6

5 report, we are able to show a solid set of cumulative actuals that include all the pre-contract cost accruals from B.U, Aerospace and MIT. While ramping up technical aspect of the project was still slower then hoped, definite progress can be seen, both from an east/west coordination and an instrument preliminary design point of view. Schedule Status For Phase A/B/C_bridge, the CRaTER Project currently works to the LRO Project Schedule V0.5. At this time, the CRaTER Project is not requesting any deviations from that schedule. It is anticipated that the LRO Project will soon release a new revision of the schedule that reflects a change in the mission PDR from July05 to Sept05 to accommodate the addition of the mini-sar to the orbiter. This schedule change does not impact the CRaTER Project. Meetings & Telecoms Weekly CRaTER project management meetings between the Principal Investigator, Project Scientist, Project Engineer and Project Manager were were held regularly. Weekly telecoms between the CRaTER project management team and NASA instrument management/systems engineering were held but not on such a regular basis, due mainly to travel requirements by key participants. Weekly telecoms between the CRaTER project management team and the rest of the CRaTER Co-Investigator team were held but not on such a regular basis, due mainly to travel requirements by key participants. Bi-weekly participation by the CRaTER PI, the other LRO Instrument PIs and the LRO Project Scientist were held regularly. The following meetings were/will be supported by the CRaTER Project Team: LRO Kick-off Meeting at GSFC(Jan 12, 2005) Internal CRaTER Team Meeting 1 at MIT (Apr 13, 2005) Technical Interface Meeting with NASA at MIT (Apr 14, 2005) Mission Assurance Meeting with NASA at MIT (Apr 26,2005) Instrument Accommodation Review at GSFC(Apr 28,2005) Internal CRaTER Team Meeting 2 at Aerospace (June 1,2005) Instrument Preliminary Design Review at MIT (June 27 & 28, 2005) LRO Preliminary Design Review at GSFC(September TBD, 2005) Internal CRaTER Team Meeting 3 (TBS) Budget & Manpower Status The CRaTER Project was able to negotiate the subcontract Aerospace Corp. The University of Tennessee subcontract was sent to UTK and is currently under review. Page 5 of 6

6 The CRaTER project is still running significantly under budget as it tries to get to ramp up ($247.3K vs. $525.8K 1 ). Financial details can be found in the May 2005 submittal of the 533Q for the project. During this period, Aerospace began to put things in place to support the engineering portion of their project. Next month they should start making assignments to support necessary project management and mission assurance tasks. At MIT, the additional work added to their SOW, since the proposal, has identified a need to bring on an electrical engineer into the group to assist the Project Engineer. This will be a new hire and the first steps of posting the position has begun. At B.U, we Actuals vs Budget decided to bring on an engineering student to help $2,000,000 develop and run simplified $1,800,000 thermal models of the CRaTER $1,600,000 instrument. That student will $1,400,000 start next month $1,200,000 $1,000,000 $800,000 $600,000 $400,000 $200,000 Sep-05 Aug-05 Jul-05 Jun-05 May-05 Apr-05 Mar-05 Feb-05 Jan , ,785 Reserves 4/27/05 BU Baseline Actuals Financial resources still do not pose any problem for the CRaTER Project to get to the next major milestone (I-PDR). $0 Risk Analysis [Note: No changes to this Period section from Apr05 Monthly Report] At this point, there are no Red (nor yellow for that matter) class risks associated with the overall CRaTER project using the NASA standard likelihood/impact classification scheme. Currently, the highest level generic risk on the project concerns sole source EEE piece parts (such as: alerts show up on a part in the as built system or flight delivered semi-custom detectors are not acceptable). After PDR, we will be able to start to identify these parts and address them specifically piece by piece as we proceed to CDR. Also using the NASA classification scheme, we do not see any red or yellow risks associated with the requirements development process currently in process. While science and spacecraft requirements are still in a state of refinement, there is nothing that appears overly threatening at this point in the overall project. On the short term (i.e. getting thru I-PDR), the biggest challenge is getting the requirements/interfaces settled and the engineering team in place. It is felt; however, that reasonable progress is being made in this area. 1 The $525.8K stated here does not include any portion of the Project Reserves. Page 6 of 6