Welcome to my homepage.


I'm Ernst J.O. (Ejo) Schrama, associate professor within the section Astrodynamics and Space Mission (A&S) at the Faculty of Aerospace Engineering at the TU Delft in the Netherlands.

About me

I obtained my Dr. title within geodesy in 1989 by defending my PhD thesis at the TU Delft, where I received my Ir. degree in 1984. Between 1984 and 1988 I was PhD student via a scholarship provided by the Netherlands Academy of Scientific Research NWO. From 1989 to 1994 I worked on a stipend provided by the Netherlands Academy of Sciences (KNAW) enabling me to visit the Space Geodesy branch at the NASA's Goddard Space Flight Center in 1990 and 1993. In 1994 I became assistant professor at the TU Delft and in 2001 I was promoted to the associated level. In 2001 and 2002 I was also part time employed at the WL Delft hydraulics company, currently called Deltares.

I'm co-investigator on the ERS-1/2 and Envisat altimeter missions and principal investigator on the TOPEX/Poseidon and Jason-1 altimeter missions, and I'm involved in numerous contract studies related to ESA’s GOCE gravity gradiometer mission. At this moment we have a contract with ESA related to the Cryosat-2 mission launched April 8, 2010. You can find me on linkedin, my articles are here and a meta-library is maintained at citeulike. The meta-library enables you to retrieve published articles in my research field.


My main interests are in orbital dynamics and gravity field mapping, application of radar satellite altimetry missions for studying tidal physics, and related ocean model data assimilation studies. Recent activities concern the interpretation of Greenland's mass balance with NASA's GRACE mission. Some latest results from our Greenland mass balance paper [pdf]:
greenland mass loss rate (Gt/yr)Greenland mass loss acceleration (Gt/yr^2)

On the left is the mass loss expressed in Gt/yr (roughly equivalent to one cubic kilometer of ice per year) for eight coastal basins in the Greenland system, and on the right  is the acceleraton in Gt/yr^2. These results were obtained from the GRACE mission between March 2003 and February 2010.


Classes that I'm involved in are: The TU Delft backboard system is in use for all information related to classes, the information below is at best a summary of what you can find on backboard.

AE4-E01 Satellite Observation Systems and Reference Systems

The exact description of this course can be found in the study guide,
Last update on ae4-e01 on 4-oct-2006

AE4-876 Physics of the Earth

I contribute to this course on the subject tides which can be found in the study guide,

AE4-890 Planetary Sciences


See blackboard at TU Delft for the lastest status of AE4-890.

For the November December course on 10 nov 2006:
Lectures on dynamics:
Background information for these lectures:
  1. Note on Kepler orbit mechnics [pdf]
  2. Note on Lagrangian points [pdf]
  3. Note on Hill equations [pdf]
  4. Note on Roche limit [pdf]
  5. A matlab script to compute Lagragian points [matlabscript] (this script requires also the orbit.m script)
  6. A maple script to verify the positions of Lagragian points L1 L2 and L3 [maplescript]
Terrestrial planets


Last update: 14-Feb-2011