diff --git a/eof/cli.py b/eof/cli.py
index e5a2432..948c96c 100644
--- a/eof/cli.py
+++ b/eof/cli.py
@@ -35,7 +35,13 @@ from eof import log
     type=click.Choice(["S1A", "S1B"]),
     help="Optionally specify Sentinel satellite to download (default: gets both S1A and S1B)",
 )
-def cli(search_path, save_dir, sentinel_file, date, mission):
+@click.option(
+    "--use-scihub",
+    is_flag=True,
+    default=False,
+    help="Use SciHub as primary provider to download orbits (default: False)",
+)
+def cli(search_path, save_dir, sentinel_file, date, mission, use_scihub):
     """Download Sentinel precise orbit files.
 
     Saves files to `save-dir` (default = current directory)
@@ -51,4 +57,5 @@ def cli(search_path, save_dir, sentinel_file, date, mission):
         sentinel_file=sentinel_file,
         mission=mission,
         date=date,
+        use_scihub=use_scihub,
     )
diff --git a/eof/download.py b/eof/download.py
index ab06273..b9db51e 100644
--- a/eof/download.py
+++ b/eof/download.py
@@ -45,7 +45,8 @@ PRECISE_ORBIT = "POEORB"
 RESTITUTED_ORBIT = "RESORB"
 
 
-def download_eofs(orbit_dts=None, missions=None, sentinel_file=None, save_dir="."):
+def download_eofs(orbit_dts=None, missions=None, sentinel_file=None, save_dir=".",
+                  use_scihub: bool = False):
     """Downloads and saves EOF files for specific dates
 
     Args:
@@ -54,6 +55,8 @@ def download_eofs(orbit_dts=None, missions=None, sentinel_file=None, save_dir=".
             No input downloads both, must be same len as orbit_dts
         sentinel_file (str): path to Sentinel-1 filename to download one .EOF for
         save_dir (str): directory to save the EOF files into
+        use_scihub (bool): use SciHub to download orbits
+            (if False SciHUb is used only as a fallback)
 
     Returns:
         list[str]: all filenames of saved orbit files
@@ -76,18 +79,51 @@ def download_eofs(orbit_dts=None, missions=None, sentinel_file=None, save_dir=".
     # First make sures all are datetimes if given string
     orbit_dts = [parse(dt) if isinstance(dt, str) else dt for dt in orbit_dts]
 
-    # Download and save all links in parallel
-    pool = ThreadPool(processes=MAX_WORKERS)
-    result_dt_dict = {
-        pool.apply_async(_download_and_write, (mission, dt, save_dir)): dt
-        for mission, dt in zip(missions, orbit_dts)
-    }
     filenames = []
-    for result in result_dt_dict:
-        cur_filenames = result.get()
-        dt = result_dt_dict[result]
-        logger.info("Finished {}, saved to {}".format(dt.date(), cur_filenames))
-        filenames.extend(cur_filenames)
+
+    if not use_scihub:
+        # Download and save all links in parallel
+        pool = ThreadPool(processes=MAX_WORKERS)
+        result_dt_dict = {
+            pool.apply_async(_download_and_write, (mission, dt, save_dir)): dt
+            for mission, dt in zip(missions, orbit_dts)
+        }
+
+        for result in result_dt_dict:
+            cur_filenames = result.get()
+            if cur_filenames is None:
+                use_scihub = True
+                continue
+            dt = result_dt_dict[result]
+            logger.info("Finished {}, saved to {}".format(dt.date(), cur_filenames))
+            filenames.extend(cur_filenames)
+    
+    if use_scihub:
+        # try to search on scihub
+        from .scihubclient import ScihubGnssClient
+        client = ScihubGnssClient()
+        query = {}
+        if sentinel_file:
+            query.update(client.query_orbit_for_product(sentinel_file))
+        else:
+            for mission, dt in zip(missions, orbit_dts):
+                result = client.query_orbit(dt, dt + timedelta(days=1),
+                                            mission, product_type='AUX_POEORB')
+                if result:
+                    query.update(result)
+                else:
+                    # try with RESORB
+                    result = client.query_orbit(dt, dt + timedelta(minutes=1),
+                                                mission,
+                                                product_type='AUX_RESORB')
+                    query.update(result)
+
+        if query:
+            result = client.download_all(query)
+            filenames.extend(
+                item['path'] for item in result.downloaded.values()
+            )
+    
     return filenames
 
 
@@ -299,7 +335,8 @@ def find_scenes_to_download(search_path="./", save_dir="./"):
     return orbit_dts, missions
 
 
-def main(search_path=".", save_dir=",", sentinel_file=None, mission=None, date=None):
+def main(search_path=".", save_dir=",", sentinel_file=None, mission=None, date=None,
+         use_scihub: bool = False):
     """Function used for entry point to download eofs"""
 
     if not os.path.exists(save_dir):
@@ -331,4 +368,5 @@ def main(search_path=".", save_dir=",", sentinel_file=None, mission=None, date=N
         missions=missions,
         sentinel_file=sentinel_file,
         save_dir=save_dir,
+        use_scihub=use_scihub,
     )
diff --git a/eof/scihubclient.py b/eof/scihubclient.py
new file mode 100644
index 0000000..9060ea8
--- /dev/null
+++ b/eof/scihubclient.py
@@ -0,0 +1,143 @@
+"""sentinelsat based client to get orbit files form scihub.copernicu.eu."""
+
+
+import re
+import logging
+import datetime
+import operator
+import collections
+from typing import NamedTuple, Sequence
+
+from .products import Sentinel as S1Product
+
+from sentinelsat import SentinelAPI
+
+
+_log = logging.getLogger(__name__)
+
+
+DATE_FMT = '%Y%m%dT%H%M%S'
+
+
+class ValidityError(ValueError):
+    pass
+
+
+class ValidityInfo(NamedTuple):
+    product_id: str
+    generation_date: datetime.datetime
+    start_validity: datetime.datetime
+    stop_validity: datetime.datetime
+
+
+def get_validity_info(products: Sequence[str],
+                      pattern=None) -> Sequence[ValidityInfo]:
+    if pattern is None:
+        # use a generic pattern
+        pattern = re.compile(
+            r'S1\w+_(?P<generation_date>\d{8}T\d{6})_'
+            r'V(?P<start_validity>\d{8}T\d{6})_'
+            r'(?P<stop_validity>\d{8}T\d{6})\w*')
+
+    keys = ('generation_date', 'start_validity', 'stop_validity')
+    out = []
+    for product_id in products:
+        mobj = pattern.match(product_id)
+        if mobj:
+            validity_data = {
+                name: datetime.datetime.strptime(mobj.group(name), DATE_FMT)
+                for name in keys
+            }
+            out.append(ValidityInfo(product_id, **validity_data))
+        else:
+            raise ValueError(
+                f'"{product_id}" does not math the regular expression '
+                f'for validity')
+
+    return out
+
+
+def lastval_cover(t0: datetime.datetime, t1: datetime.datetime,
+                  data: Sequence[ValidityInfo]) -> str:
+    candidates = [
+        item for item in data
+        if item.start_validity <= t0 and item.stop_validity >= t1
+    ]
+    if not candidates:
+        raise ValidityError(
+            f'none of the input products completely covers the requested '
+            f'time interval: [t0={t0}, t1={t1}]')
+
+    candidates.sort(key=operator.attrgetter('generation_date'), reverse=True)
+
+    return candidates[0].product_id
+
+
+class OrbitSelectionError(RuntimeError):
+    pass
+
+
+class ScihubGnssClient:
+    T0 = datetime.timedelta(days=1)
+    T1 = datetime.timedelta(days=1)
+
+    def __init__(self, user: str = "gnssguest", password: str = "gnssguest",
+                 api_url: str = "https://scihub.copernicus.eu/gnss/",
+                 **kwargs):
+        self._api = SentinelAPI(user=user, password=password, api_url=api_url,
+                                **kwargs)
+
+    def query_orbit(self, t0, t1, satellite_id: str,
+                    product_type: str = 'AUX_POEORB'):
+        assert satellite_id in {'S1A', 'S1B'}
+        assert product_type in {'AUX_POEORB', 'AUX_RESORB'}
+
+        query_padams = dict(
+            producttype=product_type,
+            platformserialidentifier=satellite_id[1:],
+            date=[t0, t1],
+        )
+        _log.debug('query parameter: %s', query_padams)
+        products = self._api.query(**query_padams)
+        return products
+
+    @staticmethod
+    def _select_orbit(products, t0, t1):
+        orbit_products = [p['identifier'] for p in products.values()]
+        validity_info = get_validity_info(orbit_products)
+        product_id = lastval_cover(t0, t1, validity_info)
+        return collections.OrderedDict(
+            (k, v) for k, v in products.items()
+            if v['identifier'] == product_id
+        )
+
+    def query_orbit_for_product(self, product,
+                                product_type: str = 'AUX_POEORB',
+                                t0_margin: datetime.timedelta = T0,
+                                t1_margin: datetime.timedelta = T1):
+        if isinstance(product, str):
+            product = S1Product(product)
+
+        t0 = product.start_time
+        t1 = product.stop_time
+
+        products = self.query_orbit(t0 - t0_margin, t1 + t1_margin,
+                                    satellite_id=product.mission,
+                                    product_type=product_type)
+        return self._select_orbit(products, t0, t1)
+
+    def download(self, uuid, **kwargs):
+        """Download a single orbit product.
+
+        See sentinelsat.SentinelAPI.download for a detailed description
+        of arguments.
+        """
+        return self._api.download(uuid, **kwargs)
+
+    def download_all(self, products, **kwargs):
+        """Download all the specified orbit products.
+
+        See sentinelsat.SentinelAPI.download_all for a detailed description
+        of arguments.
+        """
+        return self._api.download_all(products, **kwargs)
diff --git a/requirements.txt b/requirements.txt
index e5ecbfe..18eaad6 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,4 @@
 python-dateutil==2.5.1
 requests>=2.20.0
 click==6.7
+sentinelsat>=1.0
diff --git a/setup.py b/setup.py
index fd829be..e82e843 100644
--- a/setup.py
+++ b/setup.py
@@ -20,6 +20,7 @@ setuptools.setup(
         "Programming Language :: Python :: 3.6",
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
         "Programming Language :: C",
         "License :: OSI Approved :: MIT License",
         "Topic :: Scientific/Engineering",
@@ -29,6 +30,7 @@ setuptools.setup(
         "requests",
         "click",
         "python-dateutil",
+        "sentinelsat >= 1.0",
     ],
     entry_points={
         "console_scripts": [

diff --git a/eof/tests/test_eof.py b/eof/tests/test_eof.py
index e89c9be..6ac9b68 100644
--- a/eof/tests/test_eof.py
+++ b/eof/tests/test_eof.py
@@ -159,4 +159,5 @@ class TestEOF(unittest.TestCase):
             orbit_dts=["20200101"],
             sentinel_file=None,
             save_dir=",",
+            use_scihub=False,
         )

 https://qc.sentinel1.eo.esa.int discontinued
The old S1-QC site has been discontinued.
The alternative service https://qc.sentinel1.copernicus.eu should have the same API but it seems that currently it does not provided orbit files.

The recommended alternative is https://scihub.copernicus.eu/gnss which has a different API and requires authentication.

See also https://github.com/johntruckenbrodt/pyroSAR/pull/130.
eof/tests/test_eof.py::TestEOF::test_mission
eof/tests/test_eof.py::TestEOF::test_find_scenes_to_download eof/tests/test_eof.py::TestEOF::test_download_eofs_errors eof/tests/test_eof.py::TestEOF::test_main_error_args eof/tests/test_eof.py::TestEOF::test_main_nothing_found