Sentinel-1 latest datasets are Corrupted/Incomplete


I have been working on Interferometry. I download the datasets from Alaska asf API and perform the interferometry processing. Things were working very smoothly until a week ago.
I am not sure if something has changed at the backend of the API but I found that last datasets were of bigger size (~7.5G) than usual (~4G). I am a bit surprised why is it so. Is it because of any compression failure?

You can see, the image of 2023-09-20 is 3.97 G while the image of 2023-10-02 is 6.93 G. Why is it so?

Moreover, when I download it and try to process it with SNAP GPT it throws the error below

SEVERE: S1A_IW_SLC__1SDV_20231002T205220_20231002T205246_050591_061831_986B.SAFE/measurement/s1a-iw3-slc-vh-20231002t205221-20231002t205246-050591-061831-003.tiff not found
SEVERE: S1A_IW_SLC__1SDV_20231002T205220_20231002T205246_050591_061831_986B.SAFE/measurement/s1a-iw3-slc-vv-20231002t205221-20231002t205246-050591-061831-006.tiff not found
SEVERE: Unable to load quicklook S1A_IW_SLC__1SDV_20231002T205220_20231002T205246_050591_061831_986B
Index: 0, Size: 0

Error: [NodeId: TOPSAR-Split(2)] Index: 0, Size: 0

It directly says that no IW3 files are present in the path while the file exists (checked manually).

Kindly help me with this!



I have recently opened up the dataset in SNAP here also IW3 is missing.
My AOI subsets in IW3. You can see for 2023-09-21, we have IW3 but not for 2023-10-03.
I have discovered that this is happening with almost every dataset after 25th September 2023.

Is there any Sentinel-1 Capturing error?
I am very curious to know about the recent updates.


Can you check with some tool if the characteristics of the two .zip:s differ?

What is the situation if you download that product from an original Copernicus source?

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Actually, the same issue is logged here

I think there are some internal issues with the dataspace portal while compression.

Having a look to the content detail in the Copernicus Data Space Ecosystem (CDSE) portal, it looks like the product acquired on 2023-09-20 has indeed a size of 6930 MB (not 3.97 GB as reported by @harshal306 ) and that all the measurement files are present (cropped in my screenshot), that is one for each subswath and polarisation : 3 x 2 = 6

Then it looks like the complete product is available on CDSE but that for some reason, only part of the measurements are provided in the zip when downloading (and the quicklook as well).

I just raise here an hypothesis:
When downloading a product, CDSE performs first a zipping of the product (adding an overhead on the download, but that is another topic), and the zipper forgets to add some files.

So, I think this is not a platform/sensor/processing anomaly, but a transient issue with the CDSE download mechanism. I suggest that you report directly the issue to the CDSE support here ( on submit a request)



Thanks for such a clarification @ghajduch

Actually the 3.97G, I was talking about using the Alaska API (ASF Data Search).

I do agree on the Copernicus facility, the size shown is unzipped that’s why it is 6930M
However, Alaska provides the product in compressed format, I believe historic data is also around ~4G.
But this unusual spike in the size using Alaska API made me think of some issues.

I understand there is no problem with the sentinel-1 captures, the problem only belongs to the compression segment. I support your hypothesis.

nevertheless, thanks for the explanation, I will submit my query to Dataspace Copernicus directly.
Sorry for bothering.


Also, note that zip is not exactly a simple spec. zip files can be created in a number of ways. We can count atleast 6-7 number of variants of zip used for Sentinel-1 over the history of the mission, including one where data is not compressed but just organized in a zip file without compression. All of these are legitimate zipfiles and work with most zip-based sofftware. I would not worry too much about the size of the zip file as these are implementation dependent. We would however hope that the underlying zip files archived at different locations/ distribution centers are exactly the same for granular access.


ASF has a news release on the Zip file change from the new ESA hub: Sentinel-1 data file size increases | Alaska Satellite Facility

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