26 GHz FREQUENCY BAND IN THE ESTRACK DEEP SPACE NETWORK R. Abello, P. Besso OPS-GS

ESA upcoming missions K 15 Mbps X 4kbps X 5/24 1.5 L2 2020 FIRI K 40-50 Mbps X 4kbps X 4/24 1.5 L2 2015 WFI K or Ka To 1 Mbps X 75 kbps X 9/24 270 Helio Eccentric 2015 SoIO X X 400 Mars 2013 EXOMARS K 28 kbps X 7 kbps X 2 kbps 9/48 or 2.3/48 55 Helio at 1AU 2015 LISA K To 1 Mbps X 10 kbps X 4 kbps 12/24 1.5 L2 2012 DARWIN Downlink Downlink Uplink Communications Max Ground Contact hrs Max Range (1E6 km) Orbit Launch date Name

NASA/JPL upcoming missions 2013

Study Objectives Define K-Band mission requirements and to establish preliminary system specifications To develop a set of sub-system specifications based on the system specifications To investigate each major sub-system To investigate the optical/BWG solutions for each Deep Space Antenna (DSA1 and DSA2) To establish the feasibility of the introduction of K-Band reception into each of the DSA antennas

Define K-Band mission requirements and to establish preliminary system specifications

To develop a set of sub-system specifications based on the system specifications

To investigate each major sub-system

To investigate the optical/BWG solutions for each Deep Space Antenna (DSA1 and DSA2)

To establish the feasibility of the introduction of K-Band reception into each of the DSA antennas

Frequency bands Ka-Band downlink 31.8 -32.3 GHz to be used for Deep Space Missions K-Band downlink 25.5 – 27.0 GHz to be used for Moon, Lagrangian and Near Earth Missions (including Earth Observation Missions)

Ka-Band downlink 31.8 -32.3 GHz to be used for Deep Space Missions

K-Band downlink 25.5 – 27.0 GHz to be used for Moon, Lagrangian and Near Earth Missions (including Earth Observation Missions)

Communication requirements analysis Need for 35m antennas Need for cryo-LNAs CD = 0.25 average clear weather

Need for 35m antennas

Need for cryo-LNAs

CD = 0.25 average clear weather

K-Band Sky Noise 1/3

K-Band Sky Noise 2/3

K-Band Sky Noise 3/3

K-Band Sky attenuation 1/2

Impact of atmospheric attenuation on the link budget Important criterion for site selection of DSA3 in case 26 GHz is required K-Band Sky attenuation 2/2

Impact of atmospheric attenuation on the link budget

Important criterion for site selection of DSA3 in case 26 GHz is required

DSA1 Block Diagram

DSA1 antenna 1/8

Basic Philosophy Present DSA1 design including K-band upgrade University of Pavia Antenna Optics, Dichroics & Feeds DSA1 Case – Darmstadt, Germany – 06/02/2007 DSA1 antenna 2/8 Maximum reuse concept: Dual reflector Lower BWG Modifications limited to: M4 New M4b New feed in the upper BWG

Maximum reuse concept:

Dual reflector

Lower BWG

Modifications limited to:

M4

New M4b

New feed in the upper BWG

DSA1 antenna 3/8 Frequency: 25.5 – 27 GHz Polarisation: Dual Circular Tracking: K-Band

Frequency: 25.5 – 27 GHz

Polarisation: Dual Circular

Tracking: K-Band

DSA1 antenna 4/8

DSA1 antenna 5/8

DSA1 antenna 6/8

DSA1 antenna 7/8

DSA1 antenna 8/8

Size of the M4 dichroic to be manufactured is big (3.2m x 1.75m) Sag of the dichroic mirror due to gravity Big down-time of the antenna in case the upgrade is required Poor G/T compared to the DSA2 upgrade DSA1 is the only Deep Space Antenna operating in S-Band. NASA/JPL Moon mission model considers the use of S- and K-Band simultaneosly. Conclusions DSA1 upgrade

Size of the M4 dichroic to be manufactured is big (3.2m x 1.75m)

Sag of the dichroic mirror due to gravity

Big down-time of the antenna in case the upgrade is required

Poor G/T compared to the DSA2 upgrade

DSA1 is the only Deep Space Antenna operating in S-Band. NASA/JPL Moon mission model considers the use of S- and K-Band simultaneosly.

DSA2 Block Diagram

Basic Philosophy Present DSA2 design including KaTX-band upgrade Maximum reuse concept: Dual reflector Upper BWG M5 Feeds (if applicable) Modifications limited to: M6, M7, M8 Feeds University of Pavia Antenna Optics, Dichroics & Feeds DSA2 Case – Darmstadt, Germany – 06/02/2007 DSA2 antenna 1/8

Maximum reuse concept:

Dual reflector

Upper BWG

M5

Feeds (if applicable)

Modifications limited to:

M6, M7, M8

Feeds

DSA2 antenna 2/8

DSA2 antenna 3/8

DSA2 antenna 4/8

DSA2 antenna 5/8

DSA2 antenna 6/8

DSA2 antenna 7/8

DSA2 antenna 8/8

Size of the M6 dichroic does not introduce any sagging on the surface Limited down-time of the antenna in case the upgrade is required Good G/T in K-Band compared to the DSA1 upgrade Mechanical and thermal feasibility of the dual frequency X/K-Band feed to be assessed. Performance in X-Band to be improved in order not to degrade the X-Band G/T wrt the existing design Conclusions DSA2 upgrade

Size of the M6 dichroic does not introduce any sagging on the surface

Limited down-time of the antenna in case the upgrade is required

Good G/T in K-Band compared to the DSA1 upgrade

Mechanical and thermal feasibility of the dual frequency X/K-Band feed to be assessed. Performance in X-Band to be improved in order not to degrade the X-Band G/T wrt the existing design

K-Band LNAs Noise figure requirement requires cryo-LNAs using state-of-the art HEMT (InP devices) which are not commercially available. A number of institutions are willing to develop HEMT amplifiers for this application. However, the main source of concern is how to obtain InP devices.

R. Abello presentation

Next steps Refinement of the analysis of the atmospheric propagation Development of the X/K-Band feed Development of cryo-LNAs covering the 26 GHz band Undertake breadboard level development of high speed front-end DSP boards based on FPGA technology Investigate technologies and design architectures in order to minimise group delay and amplitude distortion over very wide bandwidths

Refinement of the analysis of the atmospheric propagation

Development of the X/K-Band feed

Development of cryo-LNAs covering the 26 GHz band

Undertake breadboard level development of high speed front-end DSP boards based on FPGA technology

Investigate technologies and design architectures in order to minimise group delay and amplitude distortion over very wide bandwidths

What are the other Agencies doing? 26 GHz band is the baseline for NASA Moon missions together with S-Band up- and downlink (future 21.55-22.55 GHz uplink). 26 GHz is the primary downlink of the James-Webb telescope NASA/JPL are currently upgrading their 34 m BWG antennas to 26 GHz downlink (2008 – 2010)

26 GHz band is the baseline for NASA Moon missions together with S-Band up- and downlink (future 21.55-22.55 GHz uplink).

26 GHz is the primary downlink of the James-Webb telescope

NASA/JPL are currently upgrading their 34 m BWG antennas to 26 GHz downlink (2008 – 2010)