This 2010 NASA SBIR Phase 1 proposal for an innovative Low-Field Vector Magnetometer (V-400-LF) is a response to subtopic S1.06 Particles and Field Sensors and Instrument Enabling Technologies. The V-400-LF instrument is intended for making high-resolution magnetic field measurements of planets and in interplanetary space on small satellites and spacecraft. The Phase 1 effort includes development of designs for advanced miniaturized components and a conceptual design for a miniaturized V-400-LF instrument in order to establish the feasibility of designing and fabricating a prototype V 400-LF in Phase 2. Laser-pumped helium magnetometers have proven to be world-class instruments for measuring the direction and magnitude of the geomagnetic and planetary fields. The V-400-LF will build on the heritage of the Low-field Vector Helium Magnetometer (LVHM), the Scalar Helium Magnetometer (SHM), and the laser-pumped vector/scalar Self-calibrating Vector Helium Magnetometer (SVHM). The goal of Phase 1 is development of a conceptual design for a miniaturized instrument appropriate for small spacecraft and microsatellites. This miniaturization will be accomplished through the use of advanced miniaturized components and packaging methods for the V-400-LF Sensor and Electronics. The V-400-LF can be used to measure vector components of low magnetic fields, scalar gradients (difference of vector magnitude measurements from two V-400-LF instruments), and gradient tensor elements (difference between vector components using three or more instruments) with very high stability and accuracy. The V-400-LF will have a dynamic range of +/- 1,000 nT, a sensitivity of 10 pT/rtHz at 1 Hz, and a calibrated accuracy of +/- 0.5 nT. The sample rate will be 430 Hz. The TRL is expected to be 4 at the end of the Phase 1 contract.