The Delfi-Next mission (also written as Delfi-n3Xt) is second in a development line of nanosatellites called the ‘Delfi Program’ and is successor to the successful Delfi-C3 mission. The mission statement for Delfi-Next is as follows: “Delfi-Next shall be a reliable triple-unit CubeSat of TU Delft which implements substantial advances in 1 subsystem with respect to Delfi-C3 and allows technology demonstration of 2 payloads from external partners from 2012 onwards”. The Delfi-Next mission is further specified according to the three general objectives of the Delfi program.

Delfi-n3Xt Model Space


Educational objective
The Delfi program shall provide students optimal preparation for careers in space industry. This preparation includes improvement of skills in systems engineering, teamwork, scientific writing, and communication and facilitates hands-on experience with all aspects of the development of a (small) spacecraft.

Technology demonstration objective
Delfi-n3Xt-ITRXFor Delfi-Next, the two payloads onboard are a micro-propulsion system developed by TNO in cooperation with TU Delft and University of Twente called T3µPS and an in-orbit configurable, high-efficient transceiver platform developed by ISIS BV, in cooperation with TU Delft and SystematIC BV called ITRX. Delfi-Next will carry out an onboard experiment on hydrogenated amorphous silicon solar cells from the micro-electronics institute DIMES from the TU Delft. Additionally, an experimental very low frequency receiver might be tested as precursor for the OLFAR program.

Nanosatellite bus development objective
The mission clearly states that one subsystem should be significantly advanced compared to Delfi-C3. The attitude control system plays an important role in more advanced capabilities for nanosatellites. With full three-axis active control, sun-pointing a solar array could yield more specific power, ground station tracking could be used for higher data-rates, instrument pointing can be used for remote sensing and formation flying is possible if attitude and orbit can be (relatively) controlled. Delfi‑C3 is equipped with a passive magnetic attitude control, which is unsuitable for such functionalities. As such, it is decided that Delfi-Next will be significantly advanced in the Attitude Determination and Control Subsystem compared to Delfi-C3.

T3 μPS Micro propulsion Payload

Delfi-n3Xt-Micropropulsion-payloadCold gas propulsion is the simplest configuration, requiring the least components.In a controlled manner gas is released from a tank by a valve and expelled through the thruster. Such a cold gas blow-down rocket engine typically consists of a gas tank, a pressure and temperature sensor, an on/off valve and a thruster. The micro propulsion payload has a possible application for formation flying with CubeSats. It is a Cold Gas Generator technology which is save upon launch and has a variable trust between 0 – 6 mN.

Orbital parameters

Name                 DELFI-N3XT
NORAD                39428
COSPAR designation   2013-066-N
Inclination (degree) 97.787
RAAN                 66.326
Eccentricity         0.0132333
ARGP                 95.539
Orbit per day        14.62144415
Period               1h 38m 29s (98.48 min)
Semi-major axis      7 064 km
Perigee x apogee     593 x 780 km
Drag factor          0.000720020 1/ER
Mean Anomaly         266.084


145.870 MHz CW (10dB below transponder PEP)


145.870 2400 Baud, BPSK AX.25 200mW MHz
2405.00 MHz 20-500 kbit/s, MSK, 125mW high speed, inactive.
145.880 – 145.920 MHz (inverting) 200mW PEP transponder, inactive.


435.530 – 435.570 MHz Linear transponder

Characteristics of the Communication Subsystem

Uplink Frequency 435 435
Downlink Frequency 145.870 MHz 145.870 MHz 2405 MHz
Uplink Data Rate 1200 bit/s 1200 bit/s
Downlink Data Rate 2400 bit/s 2400 – 9600 bit/s 10 – 500 kbit/s
Transmission Power 0.16 W 0.20 W 0.12 W
Modulation BPSK BPSK and CW MSK
Protocol AX25 AX25 custom
RX Power Consumption 0.22 W 0.21 W
TX Power Consumption 1.30 W 1.48 W 0.84 W


1 00371U 00371A   13325.30966725  .00000000  00000-0  10000-4 0     0
2 00371  97.7847  38.2580 0129922 191.8458 343.9172 14.62368478    09


Delfi-n3xt Communication

Delfi-n3Xt comms link overview


Where Delfi-C3 is using rascal as telemetry software, Delfi-n3xt has a new version that is called DUDe. The software will be available in the next couple of weeks. Ground stations that are using rascal will have to request a new user account when they want to automatically upload there received telemetry. One other thing that is changed, the downlink data rate is 2400 baud bpsk.

Delfi-n3Xt DUDe


Launched not active. Delfi-n3Xt is now planned for a launch in mid 2013 with a the Russian Dnepr launch vehicle expected launch November 2013 from Yasny launch site.



Homepage and other references:

Delfi Space