Data News

On  Sunday, April 26, 2015, between the hours of 12 noon (17 UTC) and 12 midnight EDT (05 UTC April 27) , changes will be implemented to NASA’s Internet access.  The purpose of this outage is to complete the Corporate Route Symmetry Project which is being implemented by the Communications Services Office (CSO).   As a result of these changes, users can expect an outage to the below services during this time period. 

Services Affected:

On  Sunday, April 26, 2015, changes to NASA’s Internet Access will have the
following impacts:

  • Internet access to/from all NASA networks
  • External Virtual Private Network (VPN) access into NASA
  • Internet access to NASA hosted public websites
  • Email to/from external locations (pps-mail) 
  • Web and mobile access to NOMAD email  ( mail)

As a result there will be disruptions to the generation of GPM and TRMM data products that will extend beyond the actual outage period. More information will be provided as it becomes available.


The issues with NOAA's 4-km Merged IR data are closed and the IMERG Early and Late Runs have been restarted from the point at which they stopped.  This will provide a continuous record for each, but it also means that it will take a while to process the backlog of data and catch up to the nominal latency. 


Due to an outage of the input 4-km IR data, the IMERG early and late runs began failing to execute on the April 14. Because of the loss of NOAA hourly IR data, PPS has had to shut off the production of NRT early and late IMERG production.  We have received no valid IR data since April 14 17:00 UTC and no IR data at all since April 15 09:00 UTC.

The software is able to deal with bad data by skipping it but it is currently not configured to handle the situation of not receiving any data at all.

We have received information that there are product problems at NOAA but have not received any information as to when the data will resume.


June 16, 2015, Update: The Tropical Rainfall Measuring Mission (TRMM) spacecraft re-entered the Earth’s atmosphere on June 15, 2015, at 11:55 p.m. EDT, over the South Indian Ocean, according to the U.S. Strategic Command’s Joint Functional Component Command for Space through the Joint Space Operations Center (JSpOC). The U.S. Space Surveillance Network, operated by the Defense Department's JSpOC, had been closely monitoring TRMM’s descent since the mission was ended in April. Most of the spacecraft was expected to burn up in the atmosphere during its uncontrolled re-entry. Learn more.


Frequently Asked Questions: TRMM Spacecraft Re-Entry

The Tropical Rainfall Measuring Mission (TRMM), a joint mission of NASA and the Japan Aerospace Exploration Agency, was launched in 1997 to study rainfall for weather and climate research. After over 17 years of productive data gathering, the instruments on TRMM were turned off on April 8 and the spacecraft will slowly descend from its orbit.


When will the TRMM spacecraft re-enter the atmosphere and burn up?

The spacecraft is estimated to reenter the atmosphere and largely burn up in mid-June 2015. It is not possible to predict in advance the exact time when re-entry will occur.


What risks are there to people and property from falling pieces of TRMM?

There is a very low risk to people and property from pieces of TRMM that reach Earth’s surface. Most of the spacecraft will burn up in the atmosphere during re-entry. Of the spacecraft's total mass (about 5,800 lbs.), 96 percent will never reach Earth. The chance that a piece of the spacecraft will strike a person is approximately 1 in 4,200.


Where will any remains of TRMM likely reach Earth's surface?

TRMM circles the Earth between the subtropical latitudes of both the northern and southern hemispheres. Due to natural variations in the near-Earth environment, a precise location of where spacecraft debris will re-enter cannot be forecast. The U.S. Space Surveillance Network, operated by the Department of Defense U.S. Strategic Command’s Joint Space Operations Center, will closely monitor the orbit of TRMM debris during its final days and issue periodic predictions of re-entry time and location.


How many NASA satellites, launch vehicles, and other large orbital debris re-enter Earth's atmosphere each year?

In recent years the number has been about half a dozen.


How many of these re-entries have resulted in confirmed personal injury or major property damage?

Since the beginning of the space age in the 1950s, there has been no confirmed report of an injury resulting from re-entering space objects.


Will some of the TRMM spacecraft remain in orbit to contribute to orbital debris?

No. After the TRMM spacecraft has re-entered, there will not be any components remaining on orbit to contribute to orbital debris.


When was the last time that a NASA science satellite re-entered Earth's atmosphere?

The Upper Atmosphere Research Satellite (UARS) re-entered in September 2011. UARS was a much larger satellite than TRMM – the size of a bus rather than an SUV. NASA received no reports of debris.


Who should be called if someone suspects they found space debris?

They should call their local authorities. The pieces of TRMM expected to survive re-entry are made of titanium or stainless steel.  Although these materials are not toxic, they could have sharp edges and should not be touched or handled by private individuals.


NASA Office of Communications
J.D. Harrington



The NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) has recently added all of the half-hourly and monthly *Final* IMERG data variables to the next generation of Giovanni, Giovanni-4 (G4). Giovanni is a Web-based application developed by the GES DISC that provides a simple and intuitive way for users to visualize, analyze, and access vast amounts of Earth science remote sensing data, without having to download the data.

Learn more:

TRMM/PR data distribution resumes during the experimental operation period. The satellite has descended to an altitude of around 350 km on February 12, 2015, which is the original nominal altitude before 2001. Verification of the data quality concluded and JAXA and PPS started distribution of PR data around the 350 km altitude (orbit number from 98231) to the public. PR available data period around 350 km altitude will be about 40 days since February 12, 2015. Please see TRMM/PR data distribution for further information and for the data locations.


PPS is re-releasing the first public version IMERG products The Integrated Multi-satellitE Retrievals for GPM (IMERG) merges precipitation estimates from passive microwave sensors, geo-IR, and monthly surface precipitation gauge analysis data (where available) to provide half-hourly and monthly precipitation estimates and related fields on a 0.1° lat./long. grid over the domain 60°N-S.  The current period of record is mid-March 2014 to the present (delayed by about 3 months) .Please refer to the IMERG Release notes , the technical IMERG document and the IMERG Algorithm Theoretical Basis Document for complete details.


On December 8, 2014 and December 10, 2014 the GPM MOC will conduct deep space calibrations maneuvers that will assist in physically verifying GMI calibration changes and also help in further characterization of the GMI instrument itself.

Special processing is required for the data collected during the DSC. Therefore, PPS production of Standard GMI products will be halted on Dec 8 at 20:30 UTC. Processing will resume during normal business hours on Dec 9.

On December 10, the maneuver is scheduled to begin at 12:00 UTC. Depending on the arrival of the DSC data processing may again be halted until the next business day.

Please note that partial or full empty granules for GMI products will be produced for the orbits covering the DSC. 


The NOAA network is gradually being restored.  MHS data appears to have started flowing around 02:00 UTC on 23 October 2014, but as of 08:00 UTC on 23 October 2014 the Meteosat geo-IR data was still  missing.  As a result, users should see reduced areas of "missing" and higher-quality estimates in general starting with the 03:00 UTC 23 October 2014 3B42RT.  


Starting about 22:00 UTC on 20 October 2014 PPS started having issues with missing input data files originating at NOAA. Informally we have been told that there is a major network issue, but have no insight on its nature or likely duration. Until this is resolved, the input data for the 3B4xRT suite of products will suffer greatly reduced volume.  Currently, we are not receiving sounder data, and the IR fields only have GOES-E and -W.